| Our research plan is to study and develop semiconductor saturable absorber mirrors (SESAMs), using quantum wells or quantum dots (nanometer scale sizes) for generating ultra-short optical pulse applications. SESAMs are novel components for passively mode-locking the lasers to generate ultra-short optical pulses. SESAMs have many applications in physics, chemistry, biology, medicine, micro-machining, optical communications, and so on. This research work includes the design, fabrication and characterization of the devices and related materials. The Processes for Making Short and Long Wavelength Semiconductor Saturable Absorber Mirrors (SESAMs) Using Gallium-Based Materials Our focus will be on SESAMs operating at around 400 - 430 nm and 1 - 1.55 µm wavelength range. We will grow GaN and related materials using metal-organic-chemical-vapor-deposition (MOCVD) to make short wavelength (around 410 nm) SESAMs, using GaInN quantum wells. We will also study GaInAsN materials and fabricate GaInAsN quantum well SESAMs for long wavelength (1 - 1.55 µm), using the molecular beam expitaxy (MBE) crystal growth method. SESAMs using GaInAs quantum dots will also be researched. Building Semiconductor Saturable Absorber Mirrors (SESAMs) into Laser Systems to Achieve Mode-Locking We will optimize the growth conditions, study the material properties by various characterization techniques, design the device structures and test with different designs for the structures. After the device fabrications are complete, the devices will be built into laser systems to achieve mode-locking, to produce pico-second to femto-second ultra-short optical pulses. |
