Single-Laser, Single-Beam Pump/Probe Thermal Lens Spectroscopy

Abstract
A unique design for a thermal lens photometer based on a single-laser/single-beam configuration is presented. The system is compatible with lock-in detection and uses a pair of acoustooptic modulators to temporally separate the pump and probe events. A minimum measurable absorbance of 6 × 10−6 cm−1 is reported. Limitations to the use of acoustooptic modulation at high absorbances are discussed.