发明名称 |
Simple, low cost, laser absorption sensor system |
摘要 |
A laser absorption sensor system for performing optical measurements on a sample is described. The sensor system includes a tunable laser, capable of being tuned at rates exceeding 1 KHZ, and with a tuning range approaching 1 GHz. The laser beam is modulated at a modulation frequency between 1 and 100 KHz. Modulation in this frequency range is termed wavelength modulation. The beam is split into two beams, a signal beam and a reference beam. The signal beam traverses the sample where characteristic absorption takes place and is incident on a signal photodetector. The reference beam is incident directly on a reference photodetector. A noise cancellation circuit combines signal and reference photo-currents from signal and reference photodetectors reducing signal noise and increasing system sensitivity. The combination of wavelength modulation and the noise cancellation scheme provide a highly sensitive simple, rugged, low cost laser absorption sensor system.
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申请公布号 |
US6040914(A) |
申请公布日期 |
2000.03.21 |
申请号 |
US19970872617 |
申请日期 |
1997.06.10 |
申请人 |
NEW FOCUS, INC. |
发明人 |
BORTZ, MICHAEL L.;GODIL, ASIF A. |
分类号 |
G01J3/433;G01N21/39;(IPC1-7):G01N21/31 |
主分类号 |
G01J3/433 |
代理机构 |
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地址 |
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