1. Fabrication. Lukáš Ondič a, Marian Varga a, Karel Hruška a, Jan Fait a,b and Peter Kapusta c

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1 Supporting information to Enhanced Extraction of Silicon-Vacancy Centers Light Emission Using Bottom-Up Engineered Polycrystalline Diamond Photonic Crystal Slabs Lukáš Ondič a, Marian Varga a, Karel Hruška a, Jan Fait a,b and Peter Kapusta c a Institute of Physics, Academy of Sciences of the Czech Republic, v.v.i., Cukrovarnická 10, CZ , Prague 6, Czech Republic; b Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, CZ , Prague 6, Czech Republic; c J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i., Dolejškova 3, CZ , Prague 8, Czech Republic 1. Fabrication Figure S1 shows SEM images of the sample in different stages of preparation process and crosssectional SEM images of the grown diamond films on reference samples. Details are described in the Methods section of the main text. (e) Fig. S1: Preparation of samples: (a) holes in PMMA prepared by EBL; (b) metal caps on SiO 2 after PMMA removal; (c) SiO 2 pillars after etching and metal removal (under angle 45 ); (d) resulting diamond photonic crystal structure (t=54 min.); (e) Cross-sectional SEM images of the reference samples grown within the same deposition as the PhC samples.

2 2. AFM measurements Figure S2a shows the morphology of the hexagonal PhC sample (30 min) measured by the AFM. Figure S2b shows the measured height profiles of the columns of the hexagonal PhCs. The AFM measurements show that the diamond pillars have dome-like shape. Due to polycrystalline nature of the material, the domes are not perfectly smooth. This roughness introduces additional optical losses to the material but does not prevent the existence of leaky modes even for the samples grown for the longest deposition time (54 min). It should be noted, that for this sample (54 min), the AFM tip already could not reach the base diamond layer at the bottom due to a high filling factor (Fig. S1d). We also applied the AFM measurements at the edge of the PhCs to determine the height of the columns. The estimated average height of the columns for all the prepared PhC structures is summarized in tab. s1. The values were computed as difference between the mean height of all pillars at the scan and the mean height of the surrounding diamond layer. The height of columns slightly increases with the increasing deposition time of diamond. Note that the size of the gap between individual pillars of PhCs and its slope may be biased due to the non-zero width of the AFM tip. Fig. S2: AFM topography: (a) Detail of the PhC with hexagonal lattice on Sample 2 (deposition time of 30 min). (b) Height profiles measured through the middle of the dome-like shape pillars of the PhC samples with the hexagonal symmetry. Deposition time [min] h PhC-hex h PhC-sq [nm] [nm] RMS [nm] Tab. S1: Mean maximal height of pillars (h PhC ) measured by the AFM and the RMS values measured on the uncorrugated part of the sample. Raw data were corrected after measurement of a reference sample with a defined height step. The graph on right side shows an example of the height profile measured at the edge of the boundary of the PhC (hexagonal, t=24min) and the uncorrugated part.

3 3. Photonic band diagrams Graphs in Figs. S3-S10 show the results of transmission measurements on samples with hexagonal and square lattice. Transmission was measured for different incident angles (step 27 ) along the main crystal axes (Γ-M and Γ-K, resp. Γ-X) and for both (TE and TM) polarizations of light. The graphs represent the photonic band diagrams of the fabricated PhC slabs. Figure S11 shows simulated photonic band diagrams for the hexagonal PhC (t=24 min), which include also losses of the material. Fig. S3: Transmission efficiency of the PhC with hexagonal lattice (t=24 min).transmission was measured for different incident angles θ (step 27 ) in the main crystal axes (Γ-M and Γ-K), for different wavelengths, and for different Fig. S4: Transmission efficiency of the PhC with hexagonal lattice (t=30 min).transmission was measured for different incident angles θ (step 27 ) in the main crystal axes (Γ-M and Γ-K), for different wavelengths, and for different

4 Fig. S5: Transmission efficiency of the PhC with hexagonal lattice (t=42 min).transmission was measured for different incident angles θ (step 27 ) in the main crystal axes (Γ-M and Γ-K), for different wavelengths, and for different Fig. S6: Transmission efficiency of the PhC with hexagonal lattice (t=54 min).transmission was measured for different incident angles θ (step 27 ) in the main crystal axes (Γ-M and Γ-K), for different wavelengths, and for different

5 Fig. S7: Transmission efficiency of the PhC with square lattice (t=24 min).transmission was measured for different incident angles θ (step 27 ) in the main crystal axes (Γ-M and Γ-X), for different wavelengths, and for different Fig. S8: Transmission efficiency of the PhC with square lattice (t=30 min).transmission was measured for different incident angles θ (step 27 ) in the main crystal axes (Γ-M and Γ-X), for different wavelengths, and for different

6 Fig. S9: Transmission efficiency of the PhC with square lattice (t=42 min).transmission was measured for different incident angles θ (step 27 ) in the main crystal axes (Γ-M and Γ-X), for different wavelengths, and for different Fig. S10: Transmission efficiency of the PhC with square lattice (t=54 min).transmission was measured for different incident angles θ (step 27 ) in the main crystal axes (Γ-M and Γ-X), for different wavelengths, and for different

7 Fig. S11 : Simulated (a) TE and (b) TM polarized photonic band diagrams of the hexagonal PhC (t=24 min.) shown within a relevant range of the incident angles with respect to the collection angle. We have added optical lossess to the simulated structure in order to find also a reasonable quantitative agreement with the measured photonic band diagrams shown in Fig. 4 (a,b).

8 4. Micro-PL measurements Fig. S12: Results of micro-pl measurements on the PhC samples. Reference spectra (black) were taken on the same samples outside the photonic crystals (planar diamond layer). Fig. S13: (a) The enhancement factor of the PhC samples having the highest extraction enhancement at the emission line of the embedded SiV centers. (b) The enhancemet factors of the PhC samples grown for 42 min.

9 5. PL decay measurements PL lifetime of the SiV centers was measured on an optical setup based on a confocal microscope. The sample was excited with a pulsed laser (exc. wavelength 514 nm, pulse width <200 fs, rep. rate 200 khz) through an objective (NA = 0.12 for the PhC sample, NA= 0.6 for the reference). The PL was collected through the same objective and sent onto a spectrograph attached to a streak camera (Hamamatsu). The objective used for the measurement with the PhC samples is similar to the one used for the integrated PL measurements in the main text. For the reference sample, however, we had to use an objective with larger NA to be able to detect reasonable signal. Figure S14 shows the PL decay curves of the hexagonal PhC and the reference grown for 24 minutes, which were spectrally integrated (+- 5 nm) around the SiV center PL peak maximum. The PL curves were fitted with single exponential functions with a lifetime equal to approximately 0.7 ns. The lifetime was within the fitting error similar for both, the PhC and the reference, suggesting that the cavity-enhanced Purcell effect is not responsible for the PL intensity enhancement of the SiV centers in our PhC sample. Fig. S14: PL decay curves of the SiV centers embedded in the hexagonal PhC grown for 24 minutes (black) and the reference grown for 24 minutes (red). The curves are fitted with single exponential functions. Both fits possess (within the fitting error) similar lifetimes (0.7 ns).