US 12,360,039 B2
Multi-spectral scattering-matrix tomography
Chia Wei Hsu, Los Angeles, CA (US); Zeyu Wang, Los Angeles, CA (US); and Yiwen Zhang, Los Angeles, CA (US)
Assigned to University of Southern California, Los Angeles, IA (US)
Filed by University of Southern California, Los Angeles, CA (US)
Filed on Oct. 24, 2022, as Appl. No. 17/972,073.
Claims priority of provisional application 63/270,828, filed on Oct. 22, 2021.
Prior Publication US 2023/0128254 A1, Apr. 27, 2023
Int. Cl. G01B 9/02091 (2022.01); G01N 21/47 (2006.01); G03H 1/04 (2006.01)
CPC G01N 21/4795 (2013.01) [G01B 9/02091 (2013.01); G03H 1/0443 (2013.01); G03H 2001/0445 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A method for multi-spectral scattering-matrix tomography comprising
a) splitting an input light signal into an incident light signal and a reference light signal, wherein the input light signal is varied over a predetermined frequency range;
b) directing the incident light signal to a sample in either a reflection configuration or a transmission configuration such that an output light signal includes light scattered from or transmitted through the sample, wherein the incident light signal is varied over a predetermined range of incident angles;
c) directing the output light signal and the reference light signal to a camera, the output light signal directed at a constant angle with respect to the reference light signal to allow for amplitude and phase to be calculated by off-axis holography;
d) measuring with the camera a total light signal that is a coherent sum of the reference light signal and the output light signal;
e) collecting the total light signal for each light frequency and each incident angle as collected total light signal data;
f) calculating with a computing device a scattering matrix or a reflection matrix or a transmission matrix from the collected total light signal data; and
g) deriving an image of the sample from the scattering matrix or reflection matrix or transmission matrix by summing over angles and summing over light frequencies, wherein an image intensity is determined from the scattering matrix by:

OG Complex Work Unit Math
where:
ISMT is the image intensity as a function of position r0 in the sample;
r0 is a position vector of a point in the sample;
S(ω, kout, kin) is an element of the scattering matrix for the incidence channel with kin and the reflection channel with kout;
kin is the wavevector of the incident light signal;
kout is the wavevector of the output (i.e., reflected) light signal; and
ω is the light frequency.