Ultradeep Imaging: High Spatial Resolution Imaging

Coherent Amplification Time-Gated Nonlinear Scattering
A scientist loading a sample into a microscope
Opportunity

Available for Licensing
TRL: 2

IP Status

US Provisional Patent

Inventors

Randy Bartels

Jeff Field

Reference No: 2021-015
Licensing Manager

Aly Hoeher
Aly.Hoeher@colostate.edu
970-491-7100

At a Glance

Researchers in the Center for Imaging and Surface Science at Colorado State University have demonstrated a new technique for generating high resolution images of live cellular functions. The current limitations of high background noise while imaging in disordered media (such as tissues) prevent imaging further than about 2 mm from the surface. The novel technique proposed would push imaging depth to > 1 cm deep into optical tissue with optical resolution, revealing far more than is capable right now.

Background

Live cell imaging offers a broader view of cellular functions than fixed cell imaging. By observing the cell in an environment where it is intaking signals and proteins and performing cellular functions like respiration, scientists are able to better study subjects like cancer morphology, viral mutations, and cell growth and death. Imaging with sub-cellular spatial resolution has driven many of these discoveries. Formation of these high-resolution images (HRI) requires coherent addition of light with a large span of angles. When these waves of light are added together, in phase, HRI can be performed. Unfortunately, HRI microscopy is only available at superficial depths in tissues because optical scattering from random refractive index (RI) randomizes the propagating waves–obscuring image information and making the tissue opaque.

Overview

This enhanced imaging technique is possible by reducing the signal-to-noise ratio through multiple coherence gating methods. By exploiting multiple mechanisms that will amplify nonlinear single scattered light and gate nonlinear scattering at a depth, this technique increases the ability to suppress MS light, and enhance imaging depth. Imaging depth will be extended with a new mechanism for suppressing MS light to boost the relative fraction of SS to MS light (the SMR of light). This strategy measures a nonlinear distortion operator and adapts it for nonlinear coherent second harmonic generation (SHG) scattering, from which high-resolution images will be extracted.

The strategy exploits the recently introduced distortion operator (DO) and adapts it for nonlinear coherent second harmonic generation (SHG) scattering. Temporal focusing will suppress nonlinear scattering away from each thin section to serve as a new mechanism to further suppress multiply scattered lines of the detected light. In other words, the impact of multiply scattered light on the illumination path is eliminated.

These improvements are likely to permit imaging at depths of >1cm, or even more.

This technique offers new concepts for deep imaging and will enable direct observation of sub-cellular biological processes at unprecedented depths and offer direct observations of live cells within intact tissues that are unperturbed by clearing reagents. This technique could allow observation of unseen live dynamics in tissue environments not accessible by current optical microscopy technology.

Benefits
  • Potentially increased imaging depth of 10x or more in live and intact tissues
  • Cells can be imaged without fixing them, thus enabling observation of live dynamics and cellular functions in tissue environments that are not currently accessible
  • Multiple methods to reduce background noise in imaging at depths in live tissue
    • The enhanced fraction of SS relative to MS light will directly translate into an increased imaging depth
    • Temporal focusing
    • Coherent field amplification
Applications
  • Live tissue imaging
    • Embryonic development
    • Cellular functions and processes
    • Cancer research
    • Virology and mutagenic effects
    • Cell growth, senescence and apoptosis
  • Live cell imaging
  • Nonlinear optical (NLO) microscopy

Last updated: December 2022