Patent ID: 8541760

Claim:
A method for calibrating a deflection unit in a TIRF microscope, with which an angle of incidence of excitation light onto a specimen is adjusted, comprising: (a) adjusting a setting of the deflection unit such that a pertaining angle of incidence is greater or smaller than an anticipated critical angle for total reflection of an excitation light on a surface of a specimen; (b) scanning the angle of incidence by varying the setting of the deflection unit in a direction of the anticipated critical angle, and measuring an intensity of an optical response of a specimen elicited by the excitation light for each setting of the deflection unit; (c) measuring the intensity of the optical response of the specimen at least for a plurality of different settings of the deflection unit until the intensity of the optical response of the specimen traverses a flank; and (d) storing the setting of the deflection unit pertaining to the flank as the setting for the critical angle for total reflection at the specimen.