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A near-minimal instance of optical cooling is experimentally presented, wherein the internal-state entropy of a single atom is reduced more than twofold by illuminating it with broadband, incoherent light. Since the rate of optical pumping by a thermal state increases monotonically with its temperature, the cooling power in this scenario increases with higher thermal occupation, an example of a phenomenon known as cooling by heating. In contrast to optical pumping using coherent, narrow-band laser light, here, we perform the same task with fiber-coupled, broadband sunlight, the brightest laboratory-accessible source of continuous blackbody radiation.
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Coherent light filter
We demonstrate efficient filtering of coherent light from a broad spectral background. A Michelson interferometer is used to effectively filter out the coherent emission of mid-infrared lasers from the co-propagating incoherent emission of a broadband thermal source. We show coherent light suppression as high as 16.9 dB without any modification of the broadband incoherent background spectrum. In addition, we demonstrate the ability to measure the spatially dependent (incoherent) thermal emission from a patterned surface, using our filter to remove a coherent signal which would otherwise overload our detection system. The demonstrated filter is rapidly tunable and wavelength-flexible, and has potential for imaging and spectroscopy applications in the presence of an otherwise overpowering coherent signal.
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- PAR ID:
- 10368512
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optics Letters
- Volume:
- 47
- Issue:
- 11
- ISSN:
- 0146-9592; OPLEDP
- Format(s):
- Medium: X Size: Article No. 2646
- Size(s):
- Article No. 2646
- Sponsoring Org:
- National Science Foundation
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