attocfm Multichannel Low Temperature Confocal Microscopes

Transcription

1 attocfm Multichannel Low Temperature Confocal Microscopes Top-Innovator , attocube systems AG - Germany. attocube systems and the logo are trademarks of attocube systems AG. Registered and/or otherwise protected in various countries where attocube systems products are sold or distributed. Other brands and names are the property of their respective owners. attocube systems AG Königinstrasse 11a D München Germany Tel.: Fax: info@attocube.com Brochure version: Top-Innovator 201

2 Cryogenic Confocal Microscopes redefining the state-of-the-art for low temperature CFM For many years, attocube has been pioneering cryogenic confocal microscopy. With the introduction of the attocfm series of confocal microscopes almost a decade ago, the optical investigation of single quantum devices on the sub-micron scale at low temperature suddenly became available as a standard tool for scientists worldwide. Now once again, the attocfm is redefining the state-of-the-art for low temperature confocal microscopy. To improve the image quality in high resolution microscopy, confocal microscopes are often used at cryogenic temperatures. At these conditions, a combination of high resolution, clear optical spectra, and reduced thermal noise can be achieved. Spectral lines become sharper as thermal broadening is typically reduced at cryogenic temperature. Optical signals become stronger as quantum efficiency improves because of reduced scattering and non-radiative recombinations. For many optical microscopy applications cryogenic temperatures are therefore inevitably required. These advantages are beneficial particularly for high resolution optical spectroscopy of semiconductor structures or single molecule detection. Thus, investigation of the emitted optical energy of the sample due to changes in the surrounding material, applied voltages, or the deposited optical energy becomes feasible. WIDE RANGE OF CRYOGENIC CONFOCAL MICROSCOPY APPLICATIONS Cryogenic Photoluminescence - quantum dot luminescence - color centers in diamond - photonic crystals - single molecules - device electroluminescence Cryogenic RAMAN - carbon nanotubes - graphene - high T c superconductors - semiconductor nanowires Graphene at.2 K Monolayer Bilayer Edge Cryogenic Lithography - multiwavelength cryogenic lithography for deterministic quantum information device fabrication With its all-new, easy-to-use and modular optical head, the attocfm opens the door to a whole new range of application fields. Whether your are working at the forefront of science in the fields of photoluminescence / fluorescence of e.g. semiconducting nanostructures (quantum dots, nano wires, photonics crystals, NV color centers, ), Raman spectroscopy (e.g. on graphene, carbon nanotubes, high-t c super- conductors) or device fabrication for quantum optics (such as deterministic in-situ lithography on self-assembled quantum dots to form strongly coupled cavities), the attocfm is the tool of choice to accelerate your research and and to achieve what matters most: creating scientific impact. KEY FEATURES AND outstanding stability for long-term experiments modular design enabling a wide range of applications compatible with low temperature and high magnetic fields complete cryogen-free systems available as top-loading or table-top setups diffraction limited spatial resolution large coarse positioning range at low temperature 000 CUSTOMER FEEDBACK 2000 G band 2D band D band Raman shift (cm -1 ) Dr. Benito Alén Millán: Thanks to the cryogen free operation and superb mechanical and thermal stability, unattended data acquisition overnight had never been so easy. This is very desirable when we perform photon anti-bunching experiments on a single quantum dot. Without any special effort, we have observed that the dot luminescence intensity remains constant within ± 7 percent over ten hours. (Molecular Beam Epitaxy group at the Instituto de Microelectrónica de Madrid)

3 attocfm I low temperature confocal microscope, free-beam optics The attocfm I has been developed to offer the highest experimental setup flexibility. This is realized by a modular beam splitter head, positioned outside the cryostat. Furthermore, the freebeam optical design allows completely independent adjustment of the excitation and collection port. Therefore, applications such as Raman spectroscopy become accessible by appropriately filtering the excitation and collection signals. 2 1 The easy handling opens up new possibilities in quantitative surface characterization in the sub-micron range. The attocfm I is available with an optional interferometric encoder for closed loop operation confocal microscope head 9 t= h t= 0h.0 μm.0 μm LONG-TERM STABILITY Spot size 0. μm PRODUCT KEY FEATURES optical setup offering highest flexibility modular beam splitter head outside of cryostat wavelength and polarization filtering of the excitation and collection signal possible large coarse positioning range at low temperatures interferometric encoders for closed loop scanning (optional) low temperature objectives with NA up to 0.82 sample monitoring via CCD camera (field of view: 7 μm) fits standard cryogenic and magnet sample spaces very broad variety of applications, ranging from classical CFM measurements to Raman spectroscopy excellent stability in high magnetic fields highest measurement sensitivity access to a large area on the sample surface x < 7 nm t = h t = 0 h y < 111 nm Landau levels of a graphene sheet as a function of magnetic field in the energy region of the optical phonon (G phonon). (attocube labs in cooperation with C. Faugeras, P. Kossacki and M. Potemski, LNCM I - Grenoble, CNRS_UJF_UPS_INSA France). 10 µm Laser spot CCD image of a calibration grating (2 µm / µm periodicity), demonstrating the large field of view of 7 μm. The sample has some defects on the surface structure which are clearly resolved. (attocube application labs, 2011) Schematic drawing of the low temperature attocfm I and the attodry1100 cyrostat (optional) 02 LT and HV compatible feedthroughs 0 microscope insert (free-beam optics) 0 superconducting magnet (optional) 0 attodry1100 cyrostat (optional) 0 ultra stable Titanium housing 07 xyz coarse positioners 08 xy scanner 09 quick exchange sample holder 10 low temperature compatible objective APPLICATION EXAMPLES solid state physics and quantum dot optics fluorescence observation biological and medical research on tissue samples in cytological and neurological applications COMPATIBLE COOLING SYSTEMS attoliquid1000/2000/ attoliquid000 (on request) attodry1100/2000/700/00 The attocfm I microscope module GaAs nanowires with a 100% wurtzite structure are studied with Raman measurements using an attocfm I at K. (measurement done in labs of Prof. S. Li, UNSW, Sydney, Australia; sample courtesy of A. Fontcuberta, École Polytechnique Fédérale de Lausanne, Switzerland)

4 Stable. Modular. Easy to use. the all-new optical head from the pioneers of cryogenic CFM rerer The novel multipurpose optical head provides an ideal platform for a large variety of measurement tasks in the field of confocal microscopy, while setting new standards for stability and ease-of-use. At the heart of the optical head, there are up to three identical channels, which can be used for confocal excitation and detection of free-beam optical signals. Each channel features a FC/APC fiber port to connect to a laser source or an appropriate detector (such as a Si detector for photoluminescence or a spectrometer for Raman measurements). The free optical beam can be adjusted conveniently via two (theta, phi) mirrors before it is sent along the optical axes with the other channels via an exchangeable dichroic beam splitter. Each channel is designed in such a way, that up to two filters plus an additional optional rotatable polarizer can be added for each of the beams. Furthermore, a broadband LED illumination allows for optical inspection of the sample together with a CCD camera.the optical beam is then guided through the center of the setup down to the low temperature compatible, high-na objective, which focuses the beam onto the sample. While the objective stays fixed, the sample is sitting on top of a stack of xyz coarse positioners and a suitable scanner for image acquisition. Typically one channel for excitation and one for detection are used in combination with appropriate filters for photoluminescence/fluorescence imaging as well as for Raman spectroscopy. New techniques such as cryogenic in-situ optical lithography use an additional third channel for exposure of an appropriate photoresist after monitoring the luminescence signal of e.g. single quantum dots in order to manufacture microcavities around those single quantum objects. Detection channel (e.g. Si detector (PL/ Fluorescence) Excitation channel Optional: Second excitation channel (e.g. for lithography) 1 2 Optical inspection channel up to three optical channels compact design highly modular exchangeable optical components (filters, polarizers, beamsplitters) quick and reliable alignment low temperature compatible objective with NA of 0.82 high spatial resolution Confocal microscope head 01 FC/APC Fiber port 02 collimator 0 mirror 0 up to two filter mounts (optional) or rotatable polarizer (optional) 0 dichroic beam splitter (exchangeable) with optional laser filter and detection filter 0 LED illumination (broadband) 07 CCD camera for inspection 08 beamsplitter 09 steering mirror for the combined beams 10 low temperature compatible objective (NA=0.82) 11 sample 12 xyz coarse positioners + XY scanner

5 Setup your own experiment flexibility you would only expect from room temperature equipment Maximum collection efficiency. Low focal displacement. low temperature compatible, high-na objectives 9 The following options regarding filters, beamsplitters and rotators can be configured for every channel of the attocfm I separately. 1 1 Collimator -> beam diameter ~ mm optional free-beam coupling (also in conjunction with attodry1000/1100 see next page); easily adjustable for different wavelengths (single mode fibers) attocube systems offers several different types of low temperature compatible objectives designed for the confocal microscopes attocfm I, II and III as well as the attocfm-dry. Choose the objective which best fits your experiment, depending on wavelength range, working distance, numerical aperture, and achromaticity. For further details, please contact attocube and consult the specification data sheets of each objective. 2 collimator, adjustable for different wavelengths 2 FC/APC coupled single mode fibers to/ from excitation laser or detector/spectrometer serve as blocking pinhole in confocal detection covering the following ranges: 0-0 nm; 0-2 nm; 0-00 nm; nm; nm; nm; nm Objective LT-IWDO LT-LWDO LT-ASWDO LT-APO/VIS/0. LT-APO/NIR/0.7 Compatible with attocfm I, II and III CFM I, attodry700 attodry700 CFM I, attodry700 Numerical aperture (NA) Working distance (WD) 1.1 mm 2.8 mm 0. mm 0.7 mm (1.1 mm) 0. mm (1.0 mm) 8 Non-polarizing cube beamsplitter Pellicle or plate beamsplitter 7 beamsplitter engaged beamsplitter dis-engaged for adjustment Polarizing cube beamsplitter Beamsplitter position easily switchable: remove from beam for beam shape control (or to disengage channel) Two additional filter mounts on beamsplitter cube: up to two 1 filters (thickness < 11 mm) or SM1 threaded lens tube filters Beamsplitter options: Default: modified Zeiss cube, compatible with any plate beamsplitter of dimensions 2.2 mm x. mm x 1.0 mm (e.g. dichroic beamsplitters nm center wavelength) Optional: polarizing beamsplitter cube Optional: non-polarizing beamsplittercube Filter drawer: up to two 1 filters (thickness < 11 mm) or SM1 threaded lens tube filters and optional rotator with/without encoder and 1 filter mount (thickness <12 mm) Theta/phi mirrors for each channel easily adjustable from the outside Spectral range nm nm 1 00 nm-100 nm (>80% transmission) Apochromatic range (δf < +/- 1.0*Δ) Semi-apochromatic range 2 (δf < +/- 2.*Δ) Environments aspheric 0 nm-1000 nm (> 90% transmission) 0 nm-1000 nm (> 80% transmission) -00 nm 2-7 nm 7-90 nm 0- nm 12-7 nm nm LT, HV, high magnetic fields Clear aperture. mm 12.0 mm.7 mm 1depending on AR coating: coating A: 00-00nm coating B: nm coating C: nm uncoated 2 δf : focal displacement, Δ = n*δ ref / (2*NA 2 ): depth of focus, n: refractive index, δ ref : wavelength used to define focal plane with max. Δ δ δ (δf < +/- 1.0*Δ) 2 range(δf < +/- 2.*Δ) 2 Optional: free-beam coupling to optical table / breadboard add-on Add-on for free-beam experiments: Some optical setups (e.g. many time-resolved experiments) consist a number of complex optical components mounted on an optical table, before the free-beam is sent onto the cold sample. For such configurations, attocube offers an optional anchoring of the attodry1000/1100 to an optical table, or a breadboard add-on. These define a fixed reference position between the external optics and the sample inside the cryostat for seamless interfacing of complex free-beam based optical setups with the cryogenic sample environment and high magnetic fields. The distance between the vertical axis of the inner vacuum tube in the cryostat and the optical table is adjustable.

6 Polarization Extinction for resonant fluorescence excitation Polarimeter for Polarization Characterization for photoluminescence & fluorescence Using a technique called polarization extinction, one gains access to resonance fluorescence, which is of utmost importance in the study of semiconductor quantum dots, color centers in diamond, and novel materials of great interest such as silicon carbide and single molecules. The excitation laser is polarized such that it is reflected by a polarizing beam splitter (s) towards the sample. The back reflected light of the laser is then blocked by the same polarizing beam splitter and further suppressed, to obtain an extinction of up to 10 with the attocfm I. The fluorescence occuring at the same optical (i.e. resonant) wavelength, but different polarization (p) can be detected. For the purpose of alignment and calibration a rotatable quarter waveplate is mounted in the combined optical path down to the cold sample. The attocfm I can be used as a polarimeter to determine the state of polarization emitted under non-resonant optical excitation, which is interesting for the study of fluorescence anisotropy in asymmetric nanostructures, such as elongated nanoparticles or single molecules. We provide the possibility to excite with a defined polarization and analyze the linear (by means of a polarizer and a half wave plate) and circular (by means of a polarizer and a quarter wave plate) polarization components of the emission. For a detailed description of the different filter options, please refer to the previous page. Configuration Configuration Excitation channel Beamsplitter rotatable polarizer* polarizing beamsplitter cube Detection channel optional: rotatable polarizer* Extinction ratio 10 Combined beam Rotatable quarter waveplate* wavelength range(s) 80-0 nm, 0-00 nm, nm, nm, nm, nm, nm Excitation channel Beamsplitter Detection channel wavelength range(s) optional: rotatable polarizer, rotatable quarter/half waveplate* non-polarizing beamsplitter cube (+ laser line filter & laser blocker) rotatable quarter/half waveplate & fixed polarizer* 80-0 nm, 0-00 nm, nm, nm, nm, nm, nm *open or closed loop rotation incl. electronics & software control *open or closed loop rotation incl. electronics & software control

7 attoraman low temperature micro-raman spectroscopy Application: Raman spectroscopy on graphene cryogenic Raman micro-spectroscopy on graphene with unprecedented spatial resolution The cryogenic Raman instrument combines a high resolution, low temperature confocal microscope with ultra sensitive Raman optics. This innovative product enables state of the art confocal Raman measurements at cryogenic environments combined with magnetic fields of up to 1 T. The attoraman is a ready-to-use system and is delivered with a Raman laser source (2 nm / nm wavelength as excitation source available), ultra-high throughput spectrometer including a peltier-cooled, back-illuminated CCD, and a state-of-the-art Raman controller/software package. The attoraman uses a set of xyz-positioners for coarse positioning of the sample over a range of several mm, and is also available with an interferometric encoder for closed loop operation. Developed particularly for cryogenic applications, the ANSxy100 scanner provides a scan range of 0 x 0 µm² even at liquid helium temperature. The Raman image is obtained by raster-scanning the sample with respect to the laser focus and measuring the spectral distribution of the Raman signal for each point. counts The figure to the left shows magneto-raman measurements recorded at K on an exfoliated single crystal of natural graphite with unprecedented spatial resolution (approx. 0. μm), while sweeping the magnetic field from -9 T to + 9 T. The data were recorded on a single graphene flake and demonstrate the crossing of the E2g phonon energy with the electron-hole separation between the valence and conduction Landau levels (-N,+M) of the Dirac cone. Resonant hybridization of the E2g phonon is a specific signature of graphene flakes which display very rich Raman scattering spectra varying strongly as a function of magnetic field [1] confocal microscope head 02 LT and HV compatible feedthroughs 0 microscope insert (free-beam optics) 0 superconducting magnet (optional) 0 attodry1100 cyrostat (optional) 0 ultra stable Titanium housing 07 xyz coarse positioners 08 xy scanner 09 sample 10 low temperature compatible objective 9 fits 2" and 1 clear bore cryostats and magnets highest flexibility and sensitivity combined with minimal light loss highly stable long term measurements ultra sensitive room temperature Raman optics state-of-the-art Raman controller/ software package The figures to the left show the magnetic field evolution of Raman spectra recorded in a region where the hybridization of E2g phonon and (-2,+1) and (-1,+2) magneto-exciton takes place. We map the Raman scattering signal over 7 x 7 μm² with 00 nm spatial resolution in different scattering bands namely red-shifted and centered on the E2g phonon peak at. T. As expected, the graphene flake appears bright in the (lower) red shifted image, but appears darker in the Raman scattering map centered on the E2g peak (upper image). Schematic drawing of the low temperature attoraman and the attodry1100 cyrostat (optional) [1] C. Faugeras et al., Phys. Rev. Lett. 107, 0807 (2011). (attocube application labs, 2011; work in cooperation with C. Faugeras, P. Kossacki, and M. Potemski, LNCM I - Grenoble, CNRS_UJF_UPS_INSA France)

8 Specifications attoraman Microscope Configuration Operating Conditions configuration compact and modular design, up to three optical channels standard configuration: 1 excitation channel, 1 detection channel temperature range magnetic field range 1.8 K.. 00 K (dependent on cryostat) T + (dependent on magnet) key benefits quick and reliable alignment of each channel, steering mirror for the operating pressure range 1E- mbar.. 1 bar (designed for exchange gas atmosphere) combined beams, exceptional long-term stability quick-exchange of optical components beamsplitters, filter mounts for up to filters / polarizers (1 diameter), optional piezoelectric rotator with filter mount Sample Positioning positioners and scanners coarse positioners ANPxyz101 with piezo scanner ANSxy100 LT-compatible objective inspection unit achromat, NA = 0.82, WD = 0. mm, confocal resolution ~0 nm (@ nm in reflection); other options see page 7 sample imaging with large field of view: ~ 7 µm (attodry), ~ µm (attoliquid) step size coarse range step scan range sample monitoring fine scan range K, K x x mm³ within coarse range; e.g.: 200 x 200 µm² sample / focus monitoring via CCD camera 0 x 0 00 K, 0 x 0 K Confocal Raman image of epitaxially grown graphene on SiC, displaying the intensity distributions of its G band from cm -1. Illumination closed loop scanning option interferometric encoders for closed loop scanning excitation wavelength range light source light power on the sample port specification 2 nm, others on request dedicated Raman laser, single mode fiber coupled typically 1 pw.. 10 mw FC/APC-connector for single mode fibers Cooling Specifications bore size cryostat designed for a 2 (0.8 mm) cryostat/magnet bore attoliquid1000/2000, attodry1000/1100/2000 optical filter Raman Signal Detection spectrometer total optical transmission filters laser line filter ultra-high transission spectrometer, f=00 mm greater 0% at 2 nm dichroic mirror and edge/notch filter for signal detection as close as 90 cm -1 to the laser line Scan Controller and Software Dedicated FPGA-based RAMAN controller providing coarse positioning and scanning signals for sample positoning and scanning in x, y, and, z direction. Control Software for extensive Raman signal data acquisition and post processing. Detector cts Graphene at.2 K Monolayer Bilayer Edge D band G band 2D band gratings typ. 00/mm and 1800/mm, others on request pixel resolution 1 cm -1 at 1800/mm grating Raman shift (cm -1 ) CCD camera back-illuminated CCD, peltier-cooled to -0 C at 20 C room temperature, 102x127 pixels, 90% quantum efficiency at 2 nm, 100 khz readout converter Optical Parameters pinhole size dependent on fibers, typically.. 9 µm mode field diameter Raman spectral data of of a graphene sample, recorded at.2 K. The qualitative redistribution between G and 2D band intensities when transversing from single to bilayer graphene is in correspondence with literature. spot size diffraction limited compatible objective systems systems with different working distances: IWDO, LWDO, LT-APO (for details please refer to the objective systems table) lateral resolution see specifications of the objectives Imaging Modes Raman confocal 2D Raman images time and single point Raman spectra 2D confocal images in reflection and transmission mode Complete microscope stick attoraman

9 Low Temperature Photolithography selected applications for cryogenic confocal microscopy Very sophisticated new techniques in device fabrication have greatly benefitted from the possibility of cryogenic in-situ optical lithography. For example, to manufacture microcavities around single quantum dots, an appropriate photoresist has to be exposed while the luminescence signal of those single quantum objects is monitored, which requires cryogenic sample temperatures. The French group around Dr. Pascale Senellart at the Laboratory for Photonics and Nanostructures at CNRS has pioneered this technique by combining confocal microscopy with in-situ optical lithography at low temperature. This way they managed to embed a single quantum object into a lithographically designed device with a yield approaching 100%. Prior to this revolutionary technique, hit rates rarely exceeded 1:10000, making previous approaches pain staking and inefficient. Based on their remarkable work [1-], attocube is now offering a commercial three channel cryogenic confocal microscope, capable of similar high yields. Using the attocfm I with three channels, low temperature quantum devices such as quantum dots can now be individually selected and addressed using their photoluminescence fingerprint. A sophisticated closed loop control system allows users to determine (and relocate) the position of each quantum device with a repeatability better than 10 nm. While two channels are used for laser excitation and detection of the quantum dot, a second laser connected to the third channel allows lithography tasks on the nanometer scale at the location of the previously located quantum device. This technique allows the researcher to create pillar-shaped micro cavities or other sophisticated structures at or around the quantum dot. [1] Dousse et al., Phys. Rev. Lett. 101, 270 (2008). [2] Dousse et al., Appl. Phys. Lett. 9, (2009). [] Loo et al., Appl. Phys. Lett. 97, (2010). REMARKABLE LONG TERM STABILITY t= 20 h t= 0 h λ = 2 nm λ = 80 nm λ = 90 nm 0. µm 0. μm 0. μm 0. μm 0. μm 0. μm Long term drift measurements recorded on a single quantum object using all three channels of the attocfm. The position drifts during 20 hrs of measurement less than ±10 nm/hr in X and Y direction. Image size is 1.2 x 1.2 μm². (attocube application labs, 2011) Closed loop control Extremely stable against vibrations Ultra low drifts Reproducible alignment method Flexibility (easy mounting of optical components like filters, polarizers, etc..) Modular optical setup Laser 70 nm PL signal COLOR SPOT ALIGNMENT WITH A RESOLUTION OF ± 1 NM The figure to the left shows a superposition of the focused spots of three CFM channels at K with the following key features: Laser 2 nm CLOSED LOOP CONTROL MINIMIZING DRIFTS - Spots alignment resolution ±1 nm - Absolute positioning (contouring) error: 12 1 μm/s - Long term drift less than 10 nm/h Objective Resist layer (attocube application labs, 2011) QDs (The scheme was generously provided by Pascale Senellart, Laboratory for Photonics and Nanostructures, CNRS, Paris,France.)

10 attoafm/cfm combined low temperature atomic force and confocal microscope, tuning fork based NV color center experiments single spin scanning probe magnetometer The tuning fork based attoafm/cfm not only allows fast optical investigation of the sample prior to detailed AFM studies, it also enables precise positioning of the AFM tip over small structures and optical control of the scanning process or any surface manipulation. Plus, optical experiments such as Raman spectroscopy and tip enhanced Raman spectroscopy (TERS) can be conducted. Needless to say that all of these tasks can be performed in extreme environments, such as ultra low temperature, high vacuum and high magnetic fields. Principle - The attoafm/cfm uses an Akiyama probe tip to investigate any tip-sample interaction forces on the nanometer scale. The Akiyama probe is typically operated in non-contact mode using a phase-locked loop to excite the probe at resonance and track any shift in frequency due to tipsample interactions. An additional PI controller keeps the frequency shift at a constant value while scanning over the surface. Simultaneously to the information provided by the Akiyama probe, the CFM reveals complementary optical information of the sample surface. Since the z-scanning motion is provided by a dedicated scanner on the side of the AFM, the focal distance between the low-temperature compatible lens and the sample does not change. µm Confocal image of the Akiyama probe in close proximity of a patterned SiO 2 /Si substrate. The image clearly shows a pronounced backscattering of light at the AFM tip apex. (attocube application labs, 2009) Principle of atomic-sized magnetic sensors using NV centers Schematic drawing of the low temperature attoafm/cfm and the surrounding liquid Helium dewar (optional) 01 LT and HV compatible feedthroughs 02 vacuum window 0 microscope insert 0 superconducting magnet (optional) 0 liquid He dewar (optional) 0 confocal microscope objective 07 AFM Akiyama probe 08 two xyz coarse positioners and xyz scanner units 09 ultra stable Titanium housing PRODUCT KEY FEATURES scan area at K: 12 x 12 µm ² independent sample scanning and scanning of the AFM module tuning fork based and PLL controlled systems available non contact measurement mode objectives with various working distances available suitable for conducting and non-conducting samples enables exact positioning of AFM tip optical access to the sample with high magnification APPLICATION EXAMPLES solid state physics and quantum dot optics fluorescence observation highly stable long term experiments on single quantum dots biological and medical research on tissue samples in cytological and neurological applications fast D-imaging COMPATIBLE COOLING SYSTEMS attoliquid1000/2000 attodry1000/1100/2000/00 (on request) The attoafm /CFM microscope module Tuning fork AFM image of the SiO 2 /Si substrate as imaged beforehand using the CFM (see figure above). The height modulation corresponds to 1 nm. (attocube application labs, 2009)

11 Specifications attoafm/cfm Application: Magnetic Field Mapping nanometer magnetic resolution achieved using the attoafm/cfm for NV-center magnetometry Microscope Setup Type AFM sensor CFM AFM specifications operation modes Combined confocal (CFM) and atomic force microscope (AFM) Akiyama probe (quartz tuning fork combined with a micromachined cantilever) attocfm I external optics head and low temperature compatible, high-na objective: NA = 0.82, WD = 0. mm, confocal resolution ~0 nm (@ nm in reflection), spectral range nm (>80% transmission) non-contact mode: amplitude modulation (AM), phase modulation (PM), frequency modulation (FM) Given its premier mechanical and thermal stability, the attoafm/cfm is being used for nanoscale magnetic imaging by placing a diamond nanocrystel containing a single nitrogen-vacancy (NV) onto the AFM cantilever tip [1]-[]. Local magnetic fields are subsequently evaluated by measuring the Zeeman shifts of the NV defect spin sublevels. In the particular case of NV-center magnetometry, an external microwave field is emitted and tuned in frequency such that local spin resonance occurs. This condition can subsequently be detected by a decrease in photoluminescence intensity of the NV-center, referred to as ODMR (optically detected magnetic resonance). Using a lock-in and feedback loop technique allows to maintain spin resonance while rastering the sample, allowing to record a local magnetic field map with nanometer resolution. PL (kcounts/s) 1 2 measured z-noise density < 200pm/ Hz (.12 ms integration time, feedback on; certified for attoliquid1000/2000 cryostats AFM tip positioning Closed loop coarse positioning range (x,y,z) Open loop scan range (x,y,z) CFM specifications External optics head (see attocfm I) light detection Sample positioning Closed loop coarse positioning range (x,y,z) Open loop scan range (x,y,z) Scan controller and software ASC00 SPM controller Operating conditions temperature range magnetic field range compatible cryostats mm* x mm x 2. mm 0 μm x 0 μm x. 00 K, 12 μm x 12 μm x 2 K (non-linearity approx. %-10% of maximum scan range) compact and modular design, up to three optical channels, standard configuration: one excitation channel, one detection channel, quick and reliable alignment of each channel, steering mirror for the combined beams, exceptional long-term stability, quick-exchange of optical components beamsplitters, filter mounts for up to filters / polarizers (1 diameter), optional piezoelectric rotator with filter mount, inspection unit sample imaging with large field of view: ~0-7 μm (depending on cryostat/distance head-field center) reflection (transmission setup available on request) mm* x mm x 2. mm 0 μm x 0 μm x. 00 K, 12 μm x 12 μm x 2 K (non-linearity approx. %-10% of maximum scan range) ASC00 SPM controller; for detailed specifications please see attocontrol section 1.8 K..00 K (dependent on cryostat system, see below; room temperature version available) T + (dependent on magnet) attoliquid1000/2000 (others on request) attodry1000/1100/2000 (others on request) Left: Simplified sketch of the scanning probe magnetometer, depicting AFM cantilever, 20 nm diamond nanocrystal, high-na objective, and microwave emitter. Right: Optically detected spin resonance spectra for different magnetic fields. ESR contrast approx. 12 %, average photon count x10 cnts/s. [1] Normalized PL References: [1] L. Rondin et al., Appl. Phys. Lett. 100, 1118 (2012) see also: [2] L. Rondin et al., Nature Communications, 2279 (201) MW frequency (GHz) PL diff (a.u.) Bz (mt) Bz (mt) Magnetic field distribution of commercial magnetic hard disk (tip-sample distance d=20 nm, image sizes 10x18 pixels@1 nm pixel size) [1]: a) Geometry of the magnetic bits b) Single iso-magnetic field image (dark areas correspond to Bz =0 mt, red arrow indicates NV defect axis) c) Dual iso-magnetic field image recorded by measuring the PL difference for two fixed microwave frequencies applied consecutivley. Dark areas correspond to Bz =0 mt, white areas to Bz =0. mt. d) Complete magnetic field distribution of same area recorded using the lock-in method. Right panel: line-cut along the white dashed line. [] J.-P. Tetienne et al., Phys. Rev. B 87, 2 (201) *effectively limited to 2 mm in x-direction to avoid tip-sample collision

12 attocfm II low temperature confocal microscope, fiber-based for ultimate stability attocfm III low temperature confocal microscope, fiber-based for transmission experiments ASC00 LDM 00 The attocfm II is a fiber-based confocal microscope, which due to its compact design minimizes any drifts, and hence offers ultimate stability at low temperatures, high magnetic fields, and high vacuum. The one-of-a-kind combination of materials allows absolutely stable single dot measurements at low temperature over weeks, even when refilling the bath cryostat with liquid Helium. Furthermore, combining the attocfm II with cryogen-free cooling solutions is easily possible, opening up new possibilities in cryogenic long-term investigations while considerably reducing operational costs. The attocfm II is available with an optional interferometric encoder for closed loop operation. Principle - A laser beam is coupled into a single mode optical fiber with the help of a 0/0 coupler. The other end of the fiber is directly coupled into the low temperature compatible objective. The single mode fiber illuminates the sample and plays the role of the blocking pinhole aperture when collecting the scattered light from the sample. This way, light entering the setup for excitation as well as light collected via reflection from the sample share the same optical path inside the single mode fiber. The 0/0 coupler makes sure that the reflected light is collected by the detector. While the wavelength range is basically limited by the range of the single mode fiber, the stability is still further enhanced compared to the free-beam configuration. ASC00 0 LDM 00 The attocfm III is a fiber-based confocal microscope similar to the attocfm II (see previous page), but due to its second fiber-based objective, it also allows for transmission measurements. Principle - A laser beam is coupled into a single mode optical fiber with the help of a 0/0 coupler. The other end of the fiber is directly coupled into the low temperature compatible objective. This serves the purpose to illuminate the sample. Using transparent specimens then allows for collecting light in transmission mode via a second low temperature compatible objective, which is also connected via a single mode fiber. In this sophisticated configuration, both objectives can be independently positioned via -axis nanopositioners (and optional scanners), and although the wavelength range is limited by the range of each single mode fiber, it can of course be different for excitation and detection. Thus, this setup offers a great amount of flexibility for a whole range of applications at variable temperatures and in high magnetic fields. For further details, see the full catalogue on page 8. For further details, see the full catalogue on page 72. Photoluminescence intensity of a triply charged InAs quantum dot vs. magnetic field (K. Karrai et. al., Hybridization of electronic states in quantum dots through photon emission, Nature (200) 27, 1). Confocal image of a tweezer structure; the tweezers are freely suspended. (C. Meyer et al., Slip-stick step-scanner for scanning probe microscopy, Rev. Sci. Instrum. (200) 7, 070). PRODUCT KEY FEATURES fiber-based for ultimate stability optional interferometric encoder for closed loop scanning large coarse positioning range at low temperatures ultra compact version for 1 inch (2. mm) setups available fits standard cryogenic and magnet sample spaces minimized drifts enable long-term measurements excellent stability in high magnetic fields highest measurement sensitivity access to a large area on the sample surface Reflection (top) and transmission (bottom) images of a Vanadium rhomb-structure on a glass substrate with a layer thickness of 0 nm and a periodicity of µm, recorded with the attocfm III (attocube application labs 2007). PRODUCT KEY FEATURES optimized for reflection and transmission experiments miniaturized microscope head designed for highest stability optimized for minimal light loss large coarse positioning range at low temperatures fits standard cryogenic and magnet sample spaces minimized drifts enable long-term measurements excellent stability in high magnetic fields highest measurement sensitivity access to a large area on the sample surface

13 attodry00 including high-na objective Montana Instruments Cryostation with implemented attocube technology Ultimate collection efficiency: NA = 0.9 attodry700 cryogen-free table top cryostat with integrated objectives The attodry00 offers a highly automated, cryogen-free low temperature platform for any optical table, while achieving stunningly low vibration levels in the nanometer range at the sample location. Equipped with five optical ports and precise temperature control capabilities, the attodry00 makes optical low temperature measurements remarkably simple and straightforward. By using a proprietary design, a complete set of attocube positioners (and scanners, if desired) together with your choice of confocal objective (see page 7 for the different options) can be implemented in the attodry00. Special care has been taken to carefully thermalize the sample (see previous page) as well as the low temperature objective, and to minimize drifts between sample and objective. Low working distances and in chamber optics enable diffraction limited spatial resolution and in particular also ultimate collection efficiency. The latter has become of paramount importance in the framework of quantum optics, where many experiments involve single photon emitters. The attodry00 with attocube s high-na objectives enables a wide range of measurements such as classical pump-probe experiments, fluorescence measurements, quantum dot investigations, Raman microscopy, and many more For further details, see the full catalogue on page 100. The attodry700 offers an ultra-high numerical aperture, apochromatic confocal table-top microscope dedicated for cryogen-free low temperature operation. To achieve this task, attocube has implemented a new apochromatic objective, providing an enhanced level of chromatic aberration correction with a numerical aperture (NA) of up to 0.9. As a result, ultra-high resolution images and spectra can be recorded with high collection efficiency, making this objective series ideal for experiments on e.g. quantum dots, photonic crystals or NV color centers in diamond. The attodry700 is compatible with any optical bench, thus allowing for easy integration into existing optical setups for fast, highly accurate, For further details, see the full catalogue on page 9. and stable confocal measurements. The dual-stage pulse tube cooler integrates a novel anti-vibration system, facilitating highly sensitive measurements in a cryogen-free environment. Further features such as easy sample exchange, fast cool-down and turn-around times, and simple operation guarantee customer satisfaction and successful experiments. cryogen-free large coarse positioning range at low temperature compact table-top system suitable for any optical table minimized drifts compatible with room temperature optical equipment high-na objective (inside chamber) 02 set of positioners incl. ATC100thermal link 0 customized radiation shield 0 attocube ready base chage 0 customized housing for min. drifts vacuum tube 02 K radiation shield 0 xyz positioner and scanner 0 high NA objective 0 optical vacuum window 0 sample 9 CUSTOMER FEEDBACK attodry00 incl. high-na objective Photo / schematic drawing of the low temperature attocfm-dry and the apochromatic, high NA objective. Université de Toulouse Dr. Bernhard Urbaszek: We are pleased with the performance of the attodry700. The good mechanical and thermal stability ensures that overnight the selected quantum dot remains within the focus of the objective. (Laboratoire de physique et chimie de nano-objets, INSA Genie Physique, Toulouse)

14 Photoluminescence Fluorescence selected applications for cryogenic confocal microscopy laser energy (ev) X 1-0mK The requirements of the microelectronic and semiconductor industry for producing increasingly smaller, faster and more powerful electronic devices drives the quest for new approaches where the conventional semiconductor components can be replaced by materials of superior properties. Due to the remarkable features of semiconductor quantum dots and improvements in designing quantum dot structures these artificial atoms are gateways to an enormous array of possible applications in the fields of quantum computing, quantum cryptography and single electron / single photon devices. Particularly, the observation of optical transitions is the main tool used in the application of quantum dots as laser emitters, storage devices or for quantum information processing. Semiconductor quantum dots have also been found to be attractive for the realization of spin quantum bits, as they can be controllably positioned, electronically coupled and embedded into active devices. These quantum bits represent the fundamental logical unit in a quantum computer. By using single electron spins in semiconductor quantum dots with a well-defined orientation, it is possible to directly measure the intrinsic spin-flip time and its dependence on magnetic fields. Photocurrent Measurements on Graphene Devices using the Fiber based attocfm Spatially resolved photocurrent measurements on a graphene field-effect device in the QHE regime are presented to study the distribution of Landau levels and its relation with macroscopic transport characteristics [1]. The exceptional stability and the ease of use of the attocfm microscope greatly facilitated these measurements and allowed for measuring working devices in magnetic fields from -9 to +9 T. [1] G. Nazin, Y. Zhang, L. Zhang, E. Sutter, P. Sutter, Nature Physics, (2010). Optical experiments on MoS 2 in an attodry1000 and attodry700 laser energy (ev) laser energy (ev) X 1-0mK gate gate voltage (mv) (mv) 1 0 gate voltage (mv) laser energy (ev) laser energy (ev) gate voltage (mv) 1 0 gate voltage (mv) gate voltage (mv) Confocal Microscopy on Quantum Dots at 0 mk A confocal microscope was manufactured for the detailed investigation of quantum dots in an ultra low temperature environment (< mk) by using photoluminescence and transmission measurement techniques inside a magnetic field of up to 7 Tesla [1]. For this purpose, a customized attocfm II module was implemented into a dilution refrigerator with a cooling power of 00 μw at 120 mk on the cold finger and a base temperature on the sample plate of less than mk. The figure shows differential transmission measurements of a InAs quantum dot embedded in a GaAs matrix at 0 mk. The pronounced deviation from the lineshape as expected from the quantum confined stark effect is due to many-particle interactions. [1] C. Latta, F. Haupt, M. Hanl, A. Weichselbaum, M. Claassen, W. Wuester, P. Fallahi, S. Faelt, L. Glazman, J. von Delft, H. E. Türeci, and A. Imamoglu, Nature 7, 27-0 (2011). Material composition and strain analysis of single semiconductor quantum dots Only recently, researchers at the University of Sheffield developed an elegantly modified Optically Detected NMR (ODNMR) technique, which allows structural analysis of strained QDs [1]. E.A. Chekhovich and his colleagues approach employs a continuous-wave, broadband radiofrequency excitation not containing certain frequencies. This method represents an inversion pattern of the radiofrequency excitation used previously. The innovative ODNMR methods prove to be an important non-invasive spectroscopy method for structural analysis especially of strained nanostructures, and requires no special preparation of the sample. Furthermore, the technique allows detailed studies of electron and hole spins for qubit applications under strong quadrupole interactions. Once initialized, the electron valley index in momentum space could be used in analogy to the electron charge or spin as an information carrier. Due to its intriguing band structure, this initialization is straightforward in monolayer Molybdenum disulfide (MoS 2 ) an atomically flat, optically active semiconductor. Photoluminescence studies carried out in collaboration between Toulouse University CNRS (France) and the Chinese Academy of Science provide experimental proof of the robustness of the valley index initialization via polarized laser excitation. The zero field measurements carried out using an attodry700 table-top cryostat show 90% polarized emission at K with still 0% of polarization remaining at room temperature [1]. Measurements in an attodry1000 magneto-cryostat in a transverse magnetic field up to 9 T at K ( T at 100 K) confirm the robust electron valley index initialization. [1] E.A. Chekhovich, et al., Nature Nanotechnology 7, (2012). Observation of Many-Body Exciton States using the attocfm I The image on the left shows a D map of the photoluminescence of a single InAs/GaAs quantum dot in a charge-tunable device as also discussed in Fig. 1 in [1]. It was found that the coupling between the semiconductor quantum dot states and the continuum of the Fermi sea gives rise to new optical transitions, manifesting the formation of many-body exciton states. The experiments are an excellent proof for the stability of the attocfm as the measurements took more than 1 hours without the need for re-alignment. [1] G. Sallen, et al., Phys. Rev. B 8, 08101(R) (2012). (Images courtesy of Bernhard Urbaszek and co-workers.) [1] N. A. J. M. Kleemans et al., Nature Physics, - 8 (2010).