High-power source of THz radiation based on orientation-patterned GaAs pumped by a fiber laser

G Imeshev,X Yu,K L Vodopyanov,M E Fermann,C Lynch,D Bliss,M M Fejer,J S Harris

doi:10.1364/oe.14.004439

Abstract

We demonstrate a new source of frequency-tunable THz wave packets based on parametric down-conversion process in orientation-patterned GaAs (OP-GaAs) that produces muW-level THz average powers at the repetition rate of 100 MHz. The OP-GaAs crystal is pumped by a compact all-fiber femtosecond laser operating at the wavelength of 2 mum. Such combination of fiber laser and OP-GaAs technologies promises a practical source of THz radiation which should be suitable for many applications including imaging and spectroscopy.

Highlights

Compact sources of THz radiation have many important industrial, medical, scientific and security applications, including gas sensing, bio-sensing, spectroscopy, imaging, quality control, nondestructive testing and explosives detection [1,2,3,4]
We demonstrate a new source of frequency-tunable THz wave packets based on parametric down-conversion process in orientationpatterned GaAs (OP-GaAs) that produces μW-level THz average powers at the repetition rate of 100 MHz
The OP-GaAs crystal is pumped by a compact all-fiber femtosecond laser operating at the wavelength of 2 μm

Summary

Introduction

Compact sources of THz radiation have many important industrial, medical, scientific and security applications, including gas sensing, bio-sensing, spectroscopy, imaging, quality control, nondestructive testing and explosives detection [1,2,3,4]. [12] where the authors achieved 240 μW THz average power from a lithium niobate crystal when pumped by a Ti:Sapphire regenerative amplifier that produced 500 mW average power (500 μJ pulse energy) Another way to increase the efficiency of pulse rectification through parametric down-conversion is the use of quasiphase-matched (QPM) nonlinear materials as was demonstrated with periodically-poled lithium niobate crystals [13,14,15]. Efficient QPM generation of THz radiation in periodically-inverted diffusion-bonded GaAs stacks had been recently demonstrated [16] using a table-top pump source that produced femtosecond pulses in the 3 4 μm wavelength range with 1 - 2 μJ pulse energies at 1 kHz repetition rate. The demonstrated combination of fiber laser and OPGaAs technologies promises a truly practical source of THz radiation

THz generation using OP-GaAs pumped by a fiber laser

Conclusions