I have been involved in nonlinear optics and biophotonics for over 15 years.
Recently we developed highly sensitive photoacoustic Z-scan (PAZ-scan) for the characterization of third order nonlinear optical absorption coefficient. It combines the advantages offered by the conventional optical Z-scan technique and the highly sensitive photoacoustic detection. We studied both saturable and reverse saturable absorbers in solutions and solids. PAZ scan technique has enormous potential in characterizing wide variety of materials.
After developing Fourier phase contrast microscope (Applied Physics Letters 2006) and common path multimodal optical microscopy (Optics Letters 2009), we focused on quantitative phase imaging. Recently we developed in-line digital holographic microscopy technique which enables simultaneous acquisition of two interferograms in order to increase the acquisition rate (Optics Letters 2010, Applied Optics 2012).