Up Close: The Center for Laser Studies University of Southern California

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The Center for Laser Studies (CLS) is a research organization within the School of Engineering at the University of Southern California. Since its founding in 1973, CLS has grown to about a dozen full-time research scientists working with about 35 graduate students on projects funded by a wide range of government and industrial agencies. Because studies of and research with lasers are frequently interdisciplinary ventures, close ties are maintained with academic departments within the University such as Electrical Engineering, Physics, Materials Science, Chemistry, Mechanical Engineering and Chemical Engineering. The need to cross traditional university department lines was one of the reasons for establishing CLS. The CLS researchers share an extensive equipment and knowledge base, which also serves as a resource facility for cooperative research with industry. This approach has led to over 200 publications in major journals and has given the Center national prominence.

Six faculty members conduct a majority of their research at CLS and an approximately equal number have experiments in residence. Examples of some of the current research projects of the primary faculty are given below:

1. Professor Elsa Garmire, Director, is studying nonlinear optical devices in a variety of materials with particular emphasis on using semiconductor nonlinearities in optically bistable devices and in optical phase conjugation. This group first demonstrated mid-infrared bistability in In As with a 3 mW threshold, the lowest threshold for any bistability reported at that time. Optical bistability occurs when a semiconductor etalon is illuminated near its bandgap. The nonlinear refractive index combined with reflection feedback causes the transmission or reflection to have two stable outputs at a single value of the input, depending on the device irradiation history. Typical results are shown in Figure 1. Currently under investigation is optical phase conjugation by means of degenerate four wave mixing with two wave mixing recently observed in Cr-doped GaAs.