Possibility of using the tunable cutoff-wavelength UV photodetectors in the application of spectrum identification of flames was investigated. An amplifying circuit with 5 x 10¹⁰ current to voltage amplification was developed and acted as the key for the study of weak-signal flame emission. Distinctive peaks in UV radiation at 310nm (OH band) and 390nm (CN/CH band) were detected in butane and candle flames among all other tested. Ratio of the two UV emission bands were determined and compared to distinguish these flames from the background room lighting and other kinds of flames.

Mr. Lai successfully developed the high gain UV detector which contributed so much to the development of the air pollution monitoring system. Also, he has shared his research experience during a physics seminar which was attended by all our undergraduate Physics students, which has stimulated students' interest towards scientific research.