AXIOMA experiment Measurements on Er 3+ :YLF Guarise Marco Padova INFN June 29, 2016 Guarise Marco (Padova INFN) AXIOMA experiment June 29, 2016 1 / 20
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, 2016 2 / 20
IRQC scheme in Er 3+ Summary 18000 cm -1 3 4 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, 2016 3 / 20
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, 2016 4 / 20
Er 3+ :YLF YLF crystal: past and present former measurements... S/N 5000 100 IR+pump (left side) only pump (right side) 20 fluorescence signal (V) 50 15 10 fluorescence signal (mv) 5 0 840.54 840.55 840.56 840.57 840.58 λ (nm)...then something bad happened! S/N 500 Guarise Marco (Padova INFN) AXIOMA experiment June 29, 2016 5 / 20
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, 2016 6 / 20
new Ti:Sa laser YLF crystal: past and present Avesta project Moscow features tunability: (690-1015) nm linewidth: < 2 GHz max output power: 1.5 W @780nm with 6.5 W pump polarization: 100% Guarise Marco (Padova INFN) AXIOMA experiment June 29, 2016 7 / 20
spectroscopic investigation lines in the 4 S 3/2 manifold fluorescence signal (a.u.) 3 2.5 2 1.5 1 0.5 0 λ c=836.709nm Γ=31pm fluorescence signal (a.u.) 6 5 4 3 2 1 0 λ c=840.565nm Γ=6pm literature δe 60 cm 1 4 nm Question Different width? 0.5 836.6 836.7 836.8 836.9 837 1 837.1 840.52 840.54 840.56 840.58 840.6 λ (nm) λ (nm) Guarise Marco (Padova INFN) AXIOMA experiment June 29, 2016 8 / 20
other scheme spectroscopic investigation pump tuned to the 4 F 7/2 level 20500 cm 1 fluorescence intensity (a.u.) 300 250 200 150 100 50 Ti:Sa +IR only TiSa 0 740.435 740.44 740.445 740.45 λ (nm) line features f c=740.444 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, 2016 9 / 20
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, 1976. (1) Guarise Marco (Padova INFN) AXIOMA experiment June 29, 2016 10 / 20
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, 2016 11 / 20
Double resonance laser: other measurements to understand multiphonon absorbtion InGaAs photodiode signal 1.5 μm fluorescence signal (a.u.) 1e+06 100000 10000 1000 100 650 700 750 800 850 900 950 1000 λ (nm) good agreement with Auzel teory! resonance absorptions 790 nm 12700 cm 1 4 I 9/2 multiplet & 960 nm 10500 cm 1 4 I 11/2 multiplet Guarise Marco (Padova INFN) AXIOMA experiment June 29, 2016 12 / 20
efficiency IRQC efficiency: possible estimation 1200 fluorescence signal Ti:Sa+IR 1000 fluorescence signal (mv) 800 600 400 200 0 0 200 400 600 800 P Ti:Sa (mw) beam section S=πr 2 1.1 10 2 cm 2 Guarise Marco (Padova INFN) AXIOMA experiment June 29, 2016 13 / 20
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 1 1 + = ɛ upβ 20 + ɛ 2 ucβ 21β 20 + ɛ 3 upβ 2 21β 20 +... = 1 1 Ip τ 1 σ 12 hνp β 21 β 20 1 β 21 ɛ uc 1 (2) (3) Max efficiency η UC @ 800 mw= 70% Guarise Marco (Padova INFN) AXIOMA experiment June 29, 2016 14 / 20
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(1 + 2 1 ) τ 3 (τ 2 α+1) τ 2 α+1 (5) Guarise Marco (Padova INFN) AXIOMA experiment June 29, 2016 15 / 20
other measurements polarization measurements 1200 1000 V(Tisa+IR-mV) V(TiSa-mV) 800 V (mv) 600 400 200 0 200 0 50 100 150 200 250 300 350 α (deg) Guarise Marco (Padova INFN) AXIOMA experiment June 29, 2016 16 / 20
Zeeman splitting: the measure apparatus permanent magnet I gap 5 cm I field 280 mt Guarise Marco (Padova INFN) AXIOMA experiment June 29, 2016 17 / 20
Zeeman splitting Zeeman splitting: the measure fluoresence signal (mv) 1500 1000 500 Ti:Sa only (left scale) Ti:Sa + IR (left scale) Ti:Sa + IR (right scale) B=0 questions B=290 mt 5000 4000 3000 2000 1000 fluoresence signal (mv) too much symmetry? linewidth? 0 840.45 840.5 840.55 840.6 840.65 λ (nm) 0 Zeeman effect } δe = µ b B 6 GHz splitting B=290 mt Guarise Marco (Padova INFN) AXIOMA experiment June 29, 2016 18 / 20
In Er:YLF further improvements and measurements 15300 cm -1 3 4 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, 2016 19 / 20
the end further improvements and measurements Thanks for your attention Guarise Marco (Padova INFN) AXIOMA experiment June 29, 2016 20 / 20