An incoherent light source excited thermal lens microscope.

We report a thermal lens microscope (TLM) based on an incoherent light source (ILS) excitation. By introducing a three-layer system into an optimized ILS-excited TLM, the sensitivity can be amplified up to 10 times for a 100-μm aqueous sample. The sensitivity enhancement originates from two additional thermal lenses formed by the heat transferred from the sample to the top and bottom layers with high temperature coefficient of refractive index. It is predicted that with a power of about 10 mW used for exciting a 100-μm sample, the limit of detection of the ILS-excited TLM can go down to 5.5 × 10-6 AU. [ABSTRACT FROM AUTHOR]