Room temperature, THz photomixing sweep oscillator and its application to spectroscopic transmission through organic materials

被引：22

作者：

Brown, ER ^{[1
]}

Bjarnason, J ^{[1
]}

Chan, TLJ ^{[1
]}

Driscoll, DC ^{[1
]}

Hanson, M ^{[1
]}

Gossard, AC ^{[1
]}

机构：

[1] Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA

来源：

REVIEW OF SCIENTIFIC INSTRUMENTS | 2004年 / 75卷 / 12期

关键词：

D O I：

10.1063/1.1808912

中图分类号：

TH7 [仪器、仪表];

学科分类号：

0804 [仪器科学与技术]; 080401 [精密仪器及机械]; 081102 [检测技术与自动化装置];

摘要：

An all-solid-state continuous-wave sweep oscillator has been developed that provides high-resolution, transmission measurements between similar to30 GHz and 3 THz. It is based on difference-frequency generation between two cw frequency-offset lasers driving an ultrafast photoconductive mixer (photomixer). The output power around 100 GHz is approximately 10 muW, falling to about 1 muW around 1 THz and 0.1 muW around 3 THz. The sweep oscillator is used with two types of detectors: a hot electron bolometer for high-sensitivity measurements of weak absorption features below 1 THz, and a room temperature Golay cell for coarse measurements anywhere between 30 GHz and 3 THz. The sweep oscillator facilitates the rapid characterization of a broad variety of materials including inorganic solids, biological materials, liquids, and gases with far greater resolution (similar to10 MHz), frequency accuracy (similar to0.1 GHz), and spectral density (similar to1 muW/MHz) than competitive wideband instruments such as Fourier-transform or time-domain spectrometers. To demonstrate the versatility of the sweep oscillator, results are presented for two diverse cases of interest: (1) fast scan, broadband (>1 THz) absorption profiles from biomaterials such as polysaccharides, and (2) slow scan, narrow-band (similar to1 GHz) atmospheric lines from water vapor. (C) 2004 American Institute of Physics.

引用

页码：5333 / 5342

页数：10

共 26 条

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