Abstract: A heating and targeting laser beam and microscope apparatus optically senses, heats to generate a effluent fluid and chemically analyzes the thermal extract fluid or fluid pyrolyzates from a microscopic particle within a heterogeneous composite sample. A transparent duct-like chamber having a bottom opening is attached to a microscope. A contact surface of the sample is raised to abut against the bottom opening, which encloses the space around the particle and also brings the particle into the common focal plane of the microscope and the converging laser beam(s). This single step avoids the complex separate focusing and sealing steps required by present day techniques.