In-situ diagnostic of femtosecond laser probe pulses for high resolution ultrafast imaging

摘要

a Concept of the transient grating induced by the shaped infrared pump pulse in a transparent dielectric. The probe signal diffracted by the transient grating is collected in the far-field. b The Kerr-induced transient grating has a period Λ and is tilted with respect to the probe axis by an angle α. The length of the transient grating is a few tens of microns while the sample can be much thicker. c Experimental setup design. d Magnified view of the setup in the dashed box of (c) to show the interacting beams and the imaging configuration. In the interaction region, the beams are in plane-wave configuration. They are, therefore, focused in the back focal plane of the microscope objective. The relay lens images the back focal plane on the camera with a magnification factor of 1. The focal length of the microscope objectives is 3.6 mm.