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We present a general theory for optical imaging of moving objects obscured by heavily scattering random media. Measurements involve collecting a series of speckle intensity images as a function of the position of a moving object. A statistical average intensity correlation can be formed with the potential to provide access to microscopic and macroscopic information about the object. For macroscopic objects and translation distances that are both large relative to the wavelength, there is a clear method to invert measurements to form an image of the hidden object. Opportunities exist for super-resolution sensing and imaging, with far-subwavelength resolution. Importantly, there is no fundamental limit to the thickness of the background randomly scattering medium, other than the practical requirement of detecting an adequate number of photons and sufficient background scatter for developed Gaussian field statistics. The approach can be generalized to any wave type and frequency, under the assumption that there is adequate temporal coherence. Applications include deep tissue in vivo imaging and sensing in and through various forms of environmental clutter. The theory also provides another dimension for intensity interferometry and entangled state detection to the case with motion of the scatterer or emitter.
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Far-field speckle correlations as a function of object position for microscopically distinguishing objects hidden in a randomly scattering medium
Super-resolution optical sensing is of critical importance in science and technology and has required prior information about an imaging system or obtrusive near-field probing. Additionally, coherent imaging and sensing in heavily scattering media such as biological tissue has been challenging, and practical approaches have either been restricted to measuring the field transmission of a single point source, or to where the medium is thin. We present the concept of far-subwavelength spatial sensing with relative object motion in speckle as a means to coherently sense through heavy scatter. Experimental results demonstrate the ability to distinguish nominally identical objects with nanometer-scale translation while hidden in randomly scattering media, without the need for precise or known location and with imprecise replacement. The theory and supportive illustrations presented provide the basis for super-resolution sensing and the possibility of virtually unlimited spatial resolution, including through thick, heavily scattering media with relative motion of an object in a structured field. This work provides enabling opportunities for material inspection, security, and biological sensing.
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- Award ID(s):
- 2131486
- PAR ID:
- 10487434
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optica
- Volume:
- 11
- Issue:
- 2
- ISSN:
- 2334-2536
- Format(s):
- Medium: X Size: Article No. 137
- Size(s):
- Article No. 137
- Sponsoring Org:
- National Science Foundation
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