Suqin Nan

Reduction of the defocusing effect in lensless ghost imaging and ghost diffraction with cosh-Gaussian modulated incoherent sources

The inhibition effect from the cosh-Gaussian modulated incoherent source on the defocusing effect is investigated theoretically in lensless ghost imaging (LGI) and ghost diffraction (LGD) systems. The corresponding numerical simulations are presented to show the influence of the cosh-Gaussian incoherent source on the defocusing effect in LGI and LGD. Compared with the widely used Gaussian incoherent source, it is shown that the defocusing effect in LGI and LGD can be greatly weakened by properly adjusting the modulation parameter ω of the cosh-Gaussian source. To explain this phenomenon, the analytical expression for point spread function of the LGI system with the cosh-Gaussian source is derived.

Experimental investigation of ghost imaging of reflective objects with different surface roughness

We present an experimental demonstration of ghost imaging of reflective objects with different surface roughness. The influence of the surface roughness, the transverse size of the test detector, and the reflective angle on the signal-to-noise ratio (SNR) is analyzed by measuring the second-order correlation of the light field based on classical statistical optics. It is shown that the SNR decreases with an increment of the surface roughness and the detector’s transverse size or a decrease of the reflective angle. Additionally, the comparative studies between the rough object and the smooth one under the same conditions are also discussed.

Ghost Imaging for a Reflected Object with Large Incident Angles

Incident angle of light source is a key factor that affects imaging resolution of direct optical imaging for a reflected target. For a large incident angle, it is easy to form the “blind area” in which the image of the object cannot be distinguished clearly. Using classical statistical optics, we study ghost imaging (GI) for a reflected object numerically and experimentally and show that by measuring the second-order correlation of light fields, a ghost-image with good quality can be retrieved in the “blind area.” Unlike transmitted ghost imaging, which is affected greatly by the transverse size of the test detector, the size has almost no effect on the resolution of reflective ghost imaging when the blind area appears.

Reflective ghost imaging free from vibrating detectors

The vibration is one of the important factors affecting imaging quality of conventional remote sensing imaging because the relative motion between the imaging system and the target can result in the degradation of imaging quality. The influence of the vibration of the detector in the test path on reflective ghost imaging (RGI) is investigated theoretically and experimentally. We analyze the effects of the vibrating amplitude and velocity. The results demonstrate that the microvibrations of the bucket detector have almost no impact on the imaging resolution and signal-to-noise ratio (SNR) of RGI, i.e., the degradation of imaging quality caused by the vibration of the detector can be overcome to some extent. Our results can be helpful for remote sensing imaging.