Logo of the Laboratory of Terahertz in Prague Laboratory of Terahertz Spectroscopy, Prague
a group of Department of Dielectrics at Institute of Physics, v.v.i.
Logo of the Institute of Physics

Equipment

1) Main THz experiments

Custom-made setup for THz time-domain spectroscopy

Suitable for measurements of samples in steady state (solids, liquids; temperature range 10 – 900 K; application of high voltage up to 1.5 kV) and for optical pump—THz probe experiments; placed in a vacuum chamber. It can be operated in two modes:

MIRA seed: For the measurement of samples in steady state the experiment is driven with a femtosecond oscillator MIRA seed and uses a recently proposed high-brightness interdigitated semiconductor TeraSED photoswitch as the THz emitter and a 1 mm thick [110]-oriented ZnTe single crystal as an electro-optic (phase-sensitive) sensor.

Peak electric field 0.1 kV/cm
Average power 0.27 mW
Energy per pulse 3.5 pJ
Peak power 0.27 kW
Photons per pulse ~1.4×1010

SPITFIRE amplifier: For the pump-probe measurement we use femtosecond amplified laser output and the THz pulses are generated via an optical rectification (difference frequency mixing) nonlinear process in a 1 mm thick [110]-oriented ZnTe crystal. An identical ZnTe crystal is used as a sensor for the phase sensitive detection.

Peak electric field 5 kV/cm
Average power 0.7 µW
Energy per pulse 0.7 nJ
Peak power 2.3 kW
Photons per pulse ~7×1011

Photo of the setup for THz spectroscopy
Fig. 1. Photo of the setup for THz spectroscopy.

Custom-made setup for THz near-field microscopy

The experiment is driven with a femtosecond oscillator VITESSE and uses an interdigitated semiconductor TeraSED photoswitch as the THz emitter and a 1 mm thick [110]-oriented ZnTe single crystal as an electro-optic (phase-sensitive) sensor.

Photo of the setup for THz near-field microscopy
Fig. 2. Photo of the setup for THz near-field microscopy.

2) Laser systems

3) Other equipment

Detailed descriptions of lasers

MIRA seed

Mira is typically used for time-domain THz transmission spectroscopy.

Manufacturer Coherent Inc.
Mean wavelength 800 nm
Pulse length 50 – 80 fs (adjustable)
Spectral bandwidth 15 – 40 nm
Repetition rate 76 MHz
Energy per pulse 8 nJ
Photons per pulse ~3.5×1010
Average power 650 mW
Pulse peak power 140 kW

Spitfire ACE regenerative amplifier

The Spitfire ACE regenerative amplifier is typically used for optical pump – THz probe experiments and/or for pumping the optical parametric amplifier (TOPAS).

Manufacturer Spectra-Physics/Newport
Pump laser Empower Q-switched Nd:YLF laser, 45 W
Seed laser MaiTai SP
Mean wavelength 800 nm
Pulse length 35 fs (adjustable)
Repetition rate 5 kHz
Energy per pulse 1 mJ
Photons per pulse ~4×1015
Average power 5 W
Pulse peak power 28 GW

VITESSE

The Vitesse system is used in conjunction with THz near field microscopy.

Manufacturer Coherent
Pump laser Verdi 4.5W
Mean wavelength 800 nm
Spectral bandwidth 10 – 15 nm
Repetition rate 80 MHz
Energy per pulse 11 nJ
Average power 1 W

TOPAS parametric amplifier

The TOPAS parametric amplifier (TOPAS = travelling-wave optical parametric amplifier of super-fluorescence) is typically used for photoexcitation in optical pump – THz probe experiments.

Manufacturer Light Conversion
Tuning range 240 – 3000 nm
Pulse length ~50 fs
Energy per pulse 1 – 100 µJ
(depending on the output wavelength)