公开(公告)号：US20170268930A1

公开(公告)日：2017-09-21

申请号：US15532247

申请日：2015-12-01

Applicant: Qrometric Limited

Inventor： Edward Maxwell Hawes ,  Timothy Freegarde ,  Matthew Himsworth

IPC: G01J3/433 ,  G01J3/40

CPC classification number: G01J3/4338 ,  G01J3/40

Abstract: There is described an apparatus (2) for measuring an amount of an analyte in a mixture. In one example, the apparatus (2) has a laser source (6) for generating a frequency-modulated laser beam (22). A cavity (36) receives the frequency-modulated laser beam (22) and a photodetector (46) obtains an intensity signal indicative of an interaction between the frequency-modulated laser beam (22) and the mixture. The apparatus (2) has a first demodulator (76) for producing a first demodulation signal. A frequency locking arrangement uses the first demodulation signal to lock a carrier frequency of the frequency-modulated laser beam (22) and a mode of the cavity (36) to each other. The apparatus has a second demodulator (50) for producing a second demodulation signal and for generating, on the basis of the second demodulation signal, an output indicative of the amount of the analyte in the mixture. Other apparatus and methods are described.