AXIOMA experiment. Measurements on Er 3+ :YLF. Guarise Marco. Padova INFN. June 29, 2016

Transcription

1 AXIOMA experiment Measurements on Er 3+ :YLF Guarise Marco Padova INFN June 29, 2016 Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

2 1 Summary 2 YLF crystal: past and present 3 spectroscopic investigation 4 Double resonance laser: other measurements to understand 5 IRQC efficiency: possible estimation 6 other measurements 7 Zeeman splitting: the measure 8 further improvements and measurements Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

3 IRQC scheme in Er 3+ Summary cm S 3/2 pump 6500 cm -1 2 IR signal 1 fluorescence signal 4 I 13/2 4 I 15/2 features GSA absorption in 1450 ± 50 nm band; long lifetime of 4 I 13/2 ; pump wavelength 840 nm; Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

4 Summary Er3+ :YLF data E (1000cm )-1 Er:YLF characteristics Guarise Marco (Padova INFN) I energy gap 10.5 ev I phonon energy 500 cm 1 I lifetime of 4 I13/2 20 ms I lifetime of 4 I11/2 5 ms I fluorescence ratio 4 S3/2 4 I13/2 0.3 I fluorescence ratio 4 S3/2 4 I15/2 0.7 AXIOMA experiment June 29, / 20

5 Er 3+ :YLF YLF crystal: past and present former measurements... S/N IR+pump (left side) only pump (right side) 20 fluorescence signal (V) fluorescence signal (mv) λ (nm)...then something bad happened! S/N 500 Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

6 YLF crystal: past and present New set-up, new crystal tests new optical windows new mounting new glue new crystal different section of laser beam Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

7 new Ti:Sa laser YLF crystal: past and present Avesta project Moscow features tunability: ( ) nm linewidth: < 2 GHz max output power: 1.5 with 6.5 W pump polarization: 100% Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

8 spectroscopic investigation lines in the 4 S 3/2 manifold fluorescence signal (a.u.) λ c= nm Γ=31pm fluorescence signal (a.u.) λ c= nm Γ=6pm literature δe 60 cm 1 4 nm Question Different width? λ (nm) λ (nm) Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

9 other scheme spectroscopic investigation pump tuned to the 4 F 7/2 level cm 1 fluorescence intensity (a.u.) Ti:Sa +IR only TiSa λ (nm) line features f c= nm Γ 4 pm S/N=35 E =750 cm 1 N 1.5 N.B: 4 I 9/2 =12750 cm 1 Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

10 Double resonance laser: other measurements to understand pump GSA Multiphonon Pump ground state absorption I (E 1 + E) = I (E 1)exp( α Stokes E) + I (E 2)exp( α Antistokes (E 2 E 1 E)) α Stokes = ( ω m) 1 {ln[n/s 0(n + 1)] 1} α Antistokes = α Stoke + 1/k B T F Auzel, Multiphonon-assisted anti-stokes and stokes fluorescence of triply ionized rare-earth ions. Physical Review B, 13(7):2809, (1) Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

11 Double resonance laser: other measurements to understand multiphonon absorbtion 10 6 orders of magnitude!! Multiphonon absorbtion of Er:YLF at 300 K Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

12 Double resonance laser: other measurements to understand multiphonon absorbtion InGaAs photodiode signal 1.5 μm fluorescence signal (a.u.) 1e λ (nm) good agreement with Auzel teory! resonance absorptions 790 nm cm 1 4 I 9/2 multiplet & 960 nm cm 1 4 I 11/2 multiplet Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

13 efficiency IRQC efficiency: possible estimation 1200 fluorescence signal Ti:Sa+IR 1000 fluorescence signal (mv) P Ti:Sa (mw) beam section S=πr cm 2 Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

14 efficiency IRQC efficiency: possible estimation N 1(up) ɛ up = N 1(up) + N = N 1σ 12 1(down) I N p 1σ 12 Consider also recycle mechanism: η UC = Nv N IR I p hν p = hν p + N 1 τ = ɛ upβ 20 + ɛ 2 ucβ 21β 20 + ɛ 3 upβ 2 21β = 1 1 Ip τ 1 σ 12 hνp β 21 β 20 1 β 21 ɛ uc 1 (2) (3) Max efficiency η 800 mw= 70% Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

15 laser pulses IRQC efficiency: possible estimation initial situation N 2(initial) = N 0σ 01 I s hν s τ 1 (4) final situation N 2(final) = N 0σ 23 I p hν p τ 2(1 1 1+(τ 2 α) ) I 1 + σ p τ 23 hν p τ 3( ) τ 3 (τ 2 α+1) τ 2 α+1 (5) Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

16 other measurements polarization measurements V(Tisa+IR-mV) V(TiSa-mV) 800 V (mv) α (deg) Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

17 Zeeman splitting: the measure apparatus permanent magnet I gap 5 cm I field 280 mt Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

18 Zeeman splitting Zeeman splitting: the measure fluoresence signal (mv) Ti:Sa only (left scale) Ti:Sa + IR (left scale) Ti:Sa + IR (right scale) B=0 questions B=290 mt fluoresence signal (mv) too much symmetry? linewidth? λ (nm) 0 Zeeman effect } δe = µ b B 6 GHz splitting B=290 mt Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

19 In Er:YLF further improvements and measurements cm F 9/2 To do low energy photon pump 1170 nm low doping concentration (0.01%) New gain chip laser Innolume pump 6500 cm -1 2 IR signal 1 red fluorescence signal 4 I 13/2 4 I 15/2 Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20

20 the end further improvements and measurements Thanks for your attention Guarise Marco (Padova INFN) AXIOMA experiment June 29, / 20