title: A versatile fiber-optic coupled system for sensitive optical spectroscopy in strong ambient light.
abstract: In this work we describe design and use of a fiber-optic based optical system for the spectroscopic studies on the samples under the presence of strong ambient light. The system is tested to monitor absorption, emission, and picosecond-resolved fluorescence transients simultaneously with a time interval of 500 ms for several hours on a biologically important sample (vitamin B2) under strong UV light. An efficient stray-light rejection ratio of the setup is achieved by the confocal geometry of the excitation and detection channels. It is demonstrated using this setup that even low optical signal from a liquid sample under strong UV-exposure for the picosecond-resolved fluorescence transient measurement can reliably be detected by ultrasensitive microchannel plate photomultiplier tube solid state detector. The kinetics of photodeterioration of vitamin B2 measured using our setup is consistent with that reported in the literature. Our present studies also justify the usage of tungsten light than the fluorescent light for the healthy preservation of food with vitamin B2.
authors.affiliation: Department of Chemical, Biological and Macromolecular Sciences, Unit for Nano Science and Technology, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098, India.
authors.forename: Sudarson Sekhar
authors.initials: SS
authors.lastname: Sinha
authors.forename: Pramod Kumar
authors.initials: PK
authors.lastname: Verma
authors.forename: Abhinandan
authors.initials: A
authors.lastname: Makhal
authors.forename: Samir Kumar
authors.initials: SK
authors.lastname: Pal
mesh_terms: D008027:Light; D055100:Optical Fibers; D010782:Photolysis; D012256:Riboflavin / Q000737:chemistry; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000295:instrumentation*; D013997:Time Factors
chemical_list: D012256:Riboflavin