Absolute evaluation of the optical transfer function of the high aperture infrared cryogenic objective.

The field of infrared detectors is experiencing a strong movement towards smaller pixel pitches, and it is now common to see pitches close to the wavelength. This raises major problems in measuring their characteristics, especially their transfer function. The latter can be measured by optical pattern projection methods using a low F/# objective, such as the spot scan method.

Experimental demonstration of second-harmonic generation in high χ metasurfaces.

Metasurfaces able to concentrate light at various wavelengths are promising for enhancing nonlinear interactions. In this Letter, we experimentally demonstrate infrared second-harmonic generation (SHG) by a multi-resonant nanostructure. A 100 GaAs layer embedded in a metal-insulator-metal waveguide is shown to support various localized resonances.

MTF measurements of a type-II superlattice infrared focal plane array sealed in a cryocooler.

In operational electro-optical systems, infrared focal plane arrays (IR FPA) are integrated in cryocoolers which induce vibrations that may strongly affect their modulation transfer function (MTF). In this paper, we present the MTF measurement of an IR FPA sealed in its cryocooler. The method we use to measure the MTF decorrelates operational constraints and the technological limitations of the IR FPA.

Multi-frame linear regressive filter for the measurement of infrared pixel spatial response and MTF from sparse data.

A challenging point in the prediction of the image quality of infrared imaging systems is the evaluation of the detector modulation transfer function (MTF). In this paper, we present a linear method to get a 2D continuous MTF from sparse spectral data. Within the method, an object with a predictable sparse spatial spectrum is imaged by the focal plane array.

Mason's rule and signal flow graphs applied to subwavelength resonant structures.

Widely used for the design of resonant electronic devices, Mason's scalar rule is adapted here to the study of resonant subwavelength optical structures. It turns out to be an efficient formalism, especially when dealing with multiple wave interference mechanisms. Indeed it allows to comprehend the underlying physical mechanisms of the structure in a straightforward way and fast analytical formulae can be retrieved.

Perfect extinction in subwavelength dual metallic transmitting gratings.

We investigate the strong electromagnetic coupling that settles in dual metallic grating structures. This coupling is evidenced to lead to a perfect optical extinction in the transmission spectrum. The behavior of this perfect extinction that strongly depends on the longitudinal space and the lateral displacement between the two gratings can be explained by a simple model that describes the interference between a propagating mode and a couple of evanescent modes.