PUMP-PROBE SETUP FOR FAR-INFRARED SUBNANOSECOND TIME-RESOLVED SPECTROSCOPY AT THE NOVOSIBIRSK FREE ELECTRON LASER Y U LI A CH OPOROVA, VASI LY GERASI M OV, H EI N Z - WI LH ELM H Ü BERS, BORI S K N YAZ EV, GEN N ADY K U LI PAN OV, V LADI M I R OVCH AR, VALERY SH AST I N , H ARALD SCH N EI DER, SERGEY SERGEEV, ROM AN Z H U K AV I N AN D N I KOLAY V I N OK U ROV BU DK ER I N ST I T U T E OF N U CLEAR PH Y SI CS, N OV OSI BI RSK N OV OSI BI RSK STAT E U N I V ERSI T Y, N OV OSI BI RSK H U M BOLDT U N I V ERSI TAET Z U BERLI N , GERM AN Y I N ST U T U T E FOR PH Y SI CS OF M I CROST RU CT U RES, N I Z H N Y N OV GOROD, RU SSI A H ELM H OLT Z -Z EN T RU M DRESDEN -ROSSEN D ORF, DRESDEN , GERM AN Y
PUMP-PROBE SYSTEM
OPTICAL SYSTEM: PUMP BEAM Cu parabolic mirror f=250 mm Golay cell 1 polarizers Flat aluminum mirror Monochromatic radiation tunable within 5– 240 µ m Si beamsplitter 180 ns 30 - 100 ps P 0.4 kW average = @5.6 MHz
OPTICAL SYSTEM: PROBE BEAM Golay cell 2 TPX lens f=150 mm Si beamsplitter Optical delay
CONTROL OF BEAMS POSITION ON A SAMPLE mimic sample holder Microbolometer Microbolometer focal plane array focal plane array Pump beam Cryostat Probe beam
CONTROL OF BEAMS POSITION ON A SAMPLE 100 PUMP intensity, a.u. FWHM 2.5 mm 3 intensity, a.u. PROBE FWFM 1 mm
DETECTION SYSTEM 2 f 2 f Probe beam detector Pump beam detector
AUTOMATION OF THE MEASURMENTS Golay detector + Lock-in amplifier at 15 Hz pump beam modulation input radiation Delay line power measured with pyroelectric detector
GE:SB STUDY 105 µ m 142 µ m 150 µ m
GE:SB STUDY: RELAXATION TIME Physical Review B 89 , 035205 (2014)
GE:SB STUDY: RELAXATION TIME λ= 106 µ m
GE:SB STUDY: 2Р+/ - AT DIFFERENT TEMPERATURES λ= 150 µ m
GE:SB STUDY: 3 Р +/- AT DIFFERENT TEMPERATURES λ= 142 µ m
SUMMARY • Pump-probe system at the Novosibirsk free electron laser has been comissioned • Test experiments with the samples, which were previously studied at FELBY, have been performed and demonstrated properly work of the system
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