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1. (WO2015118717) TERAHERTZ WAVE PHASE DIFFERENCE MEASUREMENT DEVICE

Pub. No.:    WO/2015/118717    International Application No.:    PCT/JP2014/075080
Publication Date: Fri Aug 14 01:59:59 CEST 2015 International Filing Date: Tue Sep 23 01:59:59 CEST 2014
IPC: G01N 21/3581
G01J 9/02
G01B 9/02
Applicants: HITACHI HIGH-TECHNOLOGIES CORPORATION
株式会社日立ハイテクノロジーズ
Inventors: SHIRAMIZU Nobuhiro
白水 信弘
Title: TERAHERTZ WAVE PHASE DIFFERENCE MEASUREMENT DEVICE
Abstract:
 In order to provide a high-sensitivity terahertz wave phase difference measurement system having a high S/N ratio, tetrahertz interference waves are observed using a half mirror and a movable reference mirror, and the phase difference is calculated, by a terahertz wave generation/detection device that obtains a high S/N ratio by employing a terahertz wave generator for irradiating a non-linear optical crystal with angular phase-matched pump light and seed light, and a terahertz wave detector for irradiating a non-linear optical crystal with angular phase-matched pump light and terahertz waves. In order to match the optical path length of the pump light and the terahertz waves irrespective of the position of the movable reference mirror and the position of a measured object, a first optical delay device, and a second optical delay device that operates in conjunction with movement of a movable reference mirror of a Michelson interferometer, are introduced on the optical path of the pump light.