Efficient, tunable, and coherent 018–527-THz source based on GaSe crystal

Abstract

Continuously tunable and coherent radiation in the wide range 56.8-1618 mum (0.18-5.27 THz) has been achieved as a novel and promising terahertz source based on collinear phase-matched difference frequency generation in a GaSe crystal. This source has the advantages of high coherence, simplicity for tuning, simple alignment, and stable output. The peak output power for the terahertz radiation reaches 69.4 W at a wavelength of 196 mum (1.53 THz), which corresponds to a photon conversion efficiency of 3.3%. A simple optimization of the design can yield a compact terahertz source.

Terahertz studies of the dielectric response and second-order phonons in a GaSe crystal

“…1,2 GaSe is a negative uniaxial layered semiconductor with hexagonal structure of 62 m point group with a direct band gap E g d = 2.202 eV and an indirect gap E g i = 1.995 eV at T = 300 K. The longitudinal and transverse optical phonons are located at 254 and 213 cm −1 , respectively. 3,4 Recently, GaSe was used in the generation of 0.18-5.27 THz electromagnetic waves using a differencefrequency technique 4 and also used in phase-matched optical rectification with a Ti:sapphire laser from 0.4 to 41 THz. 1 GaSe is becoming a material of choice for a THz emitter and sensor.…”

Terahertz magnetic modulator based on magnetically clustered nanoparticles

“…Although sources [9][10][11][12][13] and detectors technologies 14 have evolved rapidly over the past years, THz radiation is still difficult to manipulate mainly because of the lack of both suitable materials and efficient modulation (control) techniques. Terahertz modulation has been demonstrated by optical [15][16][17][18][19][20] , electronic [21][22][23] , and thermal [24][25] means.…”

Terahertz Frequency Metrology for Spectroscopic Applications: a Review

“…Regarding the materials used, various crystals have been explored for THz DFG, starting with simple bulk configurations in inorganic materials, such as lithium niobate (LiNbO 3 ) [74,75], lithium tantalate (LiTaO 3 ) [75,76], zinc telluride (ZnTe) [77,78], indium phosphide (InP) [79], gallium arsenide (GaAs) [80], gallium selenide (GaSe) [81,82], cadmium telluride (CdTe) [83], cadmium zinc telluride (CdZnTe) [84], and gallium phosphide (GaP) [85]. The main limitation of these sources relies on the low power achieved, due to the low efficiency of the second-order phenomenon implied in the generation.…”