Patent ID: 8184300

Claim:
An apparatus comprising: a first light source 10 that generates an optical excitation pulse 11 ; an optical system 1 aligned to receive the optical excitation pulse 11 , separate it into at least two optical sub-pulses 11 ′, 11 ″ and focus at least one sub-pulse 11 ′ onto a surface of a sample 15 to form an excitation pattern with at least one spatial phase and at least one spatial period, wherein said optical system 1 further comprises at least two plates 18 , 18 ′, and wherein the tilt of one of the at least two plates 18 , 18 ′ can be adjusted in response to a particular excitation wavelength; a second light source 16 that generates a probe beam 17 that diffracts off the sample 15 ; an optical detector 19 that detects the diffracted portion of the probe beam 17 to generate a signal; and a processor configured to process the signal from the optical detector 19 to determine a property of sample 15 , wherein said optical system 1 permits excitation patterns with measurement wavelengths between 1.2 and 11 microns.