PUMP-PROBE SETUP FOR FAR-INFRARED SUBNANOSECOND TIME-RESOLVED - - PowerPoint PPT Presentation

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

polarizers Si beamsplitter Cu parabolic mirror f=250 mm Flat aluminum mirror Golay cell 1

30 - 100 ps 180 ns @5.6 MHz

P 0.4 kW

average=

Monochromatic radiation tunable within 5– 240 µm

OPTICAL SYSTEM: PROBE BEAM

Optical delay Si beamsplitter TPX lens f=150 mm Golay cell 2

CONTROL OF BEAMS POSITION ON A SAMPLE

Microbolometer focal plane array Probe beam Pump beam Cryostat Microbolometer focal plane array mimic sample holder

CONTROL OF BEAMS POSITION ON A SAMPLE

PUMP PROBE FWHM 2.5 mm FWFM 1 mm

3

intensity, a.u. intensity, a.u.

100

DETECTION SYSTEM 2 f 2 f

Probe beam detector Pump beam detector

AUTOMATION OF THE MEASURMENTS

+ Lock-in amplifier at 15 Hz pump beam modulation Delay line Golay detector input radiation power measured with pyroelectric detector

GE:SB STUDY

105 µm 142 µm 150 µm

GE:SB STUDY: RELAXATION TIME

Physical Review B 89, 035205 (2014)

λ=106 µm

GE:SB STUDY: RELAXATION TIME

GE:SB STUDY: 2Р+/- AT DIFFERENT TEMPERATURES

λ=150 µm

GE:SB STUDY: 3Р+/- AT DIFFERENT TEMPERATURES

λ=142 µm

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