Millimeter field-of-view miniature two-photon microscopy for brain imaging in freely moving mice.

Development of miniature two-photon microscopy (m2PM) has made it possible to observe fine structure and activity of neurons in the brain of freely moving animals. However, the imaging field-of-view of existing m2PM is still significantly smaller than that of miniature single-photon microscopy. Here we report that, through the design of low-magnification objective, large field-of-view scan lens and small tilt angle microscanner, a 2.

Miniature three-photon microscopy maximized for scattered fluorescence collection.

In deep-tissue multiphoton microscopy, diffusion and scattering of fluorescent photons, rather than ballistic emanation from the focal point, have been a confounding factor. Here we report on a 2.17-g miniature three-photon microscope (m3PM) with a configuration that maximizes fluorescence collection when imaging in highly scattering regimes.

Dynamic aberration correction for conformal aircraft windows using the inner window surface and a fixed lens array.

A static solution to dynamic aberrations for conformal aircraft windows with a large range of look angles is reported. The solution uses the inner window surface and a fixed lens array near the image plane to correct the dynamic window aberrations at different look angles. The inner window surface is first used to balance the dynamic aberrations of the full field of regard.

Optimization method of multilayer diffractive optical elements with consideration of ambient temperature.

A method for the optimal design of multilayer diffractive optical elements (MLDOEs) with consideration of ambient temperature is presented to improve the image quality over the entire temperature range. The relationship between diffraction efficiency and temperature is analyzed, and an optimization process of surface relief height for the MLDOEs is given. A practical 3-5 μm athermal hybrid optical system with a double-layer diffractive optical element is designed in the temperature range from -20°C to 60°C, and the image quality of two hybrid optical systems with optimized MLDOE and original MLDOE is compared.

Substrate material selection method for multilayer diffractive optics in a wide environmental temperature range.

We present a substrate material selection method for multilayer diffractive optical elements (MLDOEs) to obtain high polychromatic integral diffraction efficiency (PIDE) in a wide environmental temperature range. The extended expressions of the surface relief heights for the MLDOEs are deduced with consideration of the influence of the environmental temperature. The PIDE difference Δη¯(λ) and PIDE change factor F are introduced to select a reasonable substrate material combination.

Aberration and boresight error correction for conformal aircraft windows using the inner window surface and tilted fixed correctors.

A static solution to aberrations and boresight error for tilted conformal aircraft windows at different look angles is reported. The solution uses the inner window surface to correct the window aberrations at a 0° look angle and uses fixed correctors behind the window to correct the residual window aberrations at other look angles. Then, the boresight error for the window at different look angles is corrected by tilting the fixed correctors.