| 摘要 |
An optical device for placement in the optical train of an optical microscope, in order to detect light momentum changes to measure optical forces acting on a microscopical sample (100) located in a suspending medium inside a chamber (200), comprises a collector (10) having a numerical-aperture greater than the refraction index n m of the medium, a light sensor (15) placed at an optical equivalent of the back focal plane of the collector, a first optical relay (11) to project the collected light onto the light sensor, a second optical relay (12) placed along the illumination path of the microscope and a reference element (14) placed along said illumination path, the distance between the second optical relay and the reference element being such that, when the reference element is in focused as seen through the microscope, the diameter of the light pattern on the light sensor is 2·f d ·n m , where f d is the focal length of the device. |
