Note: A simple multi-channel optical system for modulation spectroscopies.
Rev Sci Instrum
; 88(12): 126107, 2017 Dec.
Article
in En
| MEDLINE
| ID: mdl-29289180
ABSTRACT
Photoreflectance-difference (PR/PRD) and reflectance-difference (RD) spectroscopies employ synchronic detection usually with lock-in amplifiers operating at moderate (200-1000 Hz) and high (50-100 KHz) modulation frequencies, respectively. Here, we report a measurement system for these spectroscopies based on a multichannel CCD spectrometer without a lock-in amplifier. In the proposed scheme, a typical PRD or RD spectrum consists of numerical subtractions between a thousand CCD captures recorded, while a photoelastic modulator is either operating or inhibited. This is advantageous and fits the slow response of CCD detectors to high modulation frequencies. The resulting spectra are processed with Savitzky-Golay filtering and compared well with those measured with conventional scanning systems based on lock-in amplifiers.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Rev Sci Instrum
Year:
2017
Document type:
Article
Affiliation country:
Mexico