Detailed description and schematics for our EBS instrument can be found in Refs. 7 and 13. In brief, broadband visible light from a supercontinuum laser source (SuperK Extreme EXW-6, NKT Photonics A/S, Birkerød, Denmark) is coupled into a single-mode fiber (Thorlabs, Newton, New Jersey; mode field diameter of 4.6 μm at 680 nm) and collimated to an beam diameter. The beam then passes through a linear polarizer and an iris that reduces its diameter to 2 mm in size before being directed onto the biopsy. Light backscattered from the sample is then collected by a nonpolarizing antireflection coated plate beam splitter, passes through a linear polarizer to detect the copolarized channel, and is focused onto a CCD camera (PIXIS 1024B eXcelon, Princeton Instruments, Trenton, New Jersey) by a 100 mm focal length achromatic lens. A liquid crystal tunable filter (VariSpec, PerkinElmer, Waltham, Massachusetts) attached to the camera separates the light into its component wavelengths. This configuration detects angular backscattering of up to 7.5776 deg with 0.0074 deg resolution and wavelengths between 500 and 720 nm with a 20 nm filter bandwidth. After inverse Fourier transform, this provides a minimum spatial resolution of 3.78 μm (at ) and a maximum spatial range of 5.42 mm (at ).