Semiconductor emitter based 32-channel spectrophotometer module for real-time process measurements

Heimo Keränen, Jouko Malinen

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

5 Citations (Scopus)


A new type of semiconductor emitter based multichannel spectrophotometer has been designed and tested. The spectrophotometer consists of a small electrically conirolled narrow band light source an optical receiver and microprocessor electronics for data processing. The light source is based on a 32-element GaAs and GaAIAs LED chip array which is connected to a diffraction grating and feedback optics. The source is capable of emitting intensity-stabilized single-beam narrow band light pulses. The wavelength of the light pulse can be selected by the electronics without using any moving parts. The optical mechanical and optoelectronic parts of the source have been integrated to form a compact hybrid construction. Main characteristics have been tested with an experimental 32-channel spectrophotometer designed for the wavelength range 810 nm - 1060 nm. Measured wavelength half-power bandwidths are 8 nm and channel separation is 7. 5 nm. A single spectrum scan can be recorded in 8 ms. 64 scans are averaged by the microprocessor electronics and data is transferred to a PC for a multicomponent spectrum analysis program. Output light power level is better than i05 times the averaged detector noise level. The wavelength range used is optimized for near infrared transmittance (NIT) analysis of agricultural products.
Original languageEnglish
Title of host publicationIn-Process Optical Measurements and Industrial Methods
EditorsH.A. Macleod, Peter Langenbeck
PublisherInternational Society for Optics and Photonics SPIE
Number of pages8
ISBN (Print)978-0-8194-0313-1
Publication statusPublished - 1990
MoE publication typeA4 Article in a conference publication
EventInternational Congress on Optical Science & Engineering - The Hague, Netherlands
Duration: 12 Mar 199016 Mar 1990

Publication series

SeriesProceedings of SPIE


ConferenceInternational Congress on Optical Science & Engineering
CityThe Hague

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