Simultaneous spatial frequency modulation imaging and micromachining with a femtosecond laser

Interferometric spatial frequency modulation imaging

Interferometric spatial frequency modulation for imaging (I-SPIFI) is demonstrated for the first time, to our knowledge. Significantly, this imaging modality can be seamlessly combined with nonlinear SPIFI imaging and operates through single-element detection, making it compatible for use in scattering specimens. Imaging dynamic processes with submicrometer axial resolution through long working distance optics is shown, and high contrast images compared to traditional wide-field microscopy images. Finally, enhanced lateral resolution is achieved in I-SPIFI. To our knowledge, this is the first single platform that enables multimodal linear and nonlinear imaging, with enhanced resolution, all of which can be performed simultaneously.

Three-dimensional single-pixel imaging of incoherent light with spatiotemporally modulated illumination

We derive analytic expressions for the three-dimensional coherent transfer function (CTF) and coherent spread function (CSF) for coherent holographic image reconstruction by phase transfer (CHIRPT) microscopy with monochromatic and broadband illumination sources. The 3D CSF and CTF were used to simulate CHIRPT images, and the results show excellent agreement with experimental data. Finally, we show that the formalism presented here for computing the CSF/CTF pair in CHIRPT microscopy can be readily extended to other forms of single-pixel imaging, such as spatial-frequency-modulated imaging.

Fabrication and characterization of modulation masks for multimodal spatial frequency modulated microscopy

Spatial frequency modulated imaging (SPIFI) is a powerful imaging method that when used in conjunction with multiphoton contrast mechanisms has the potential to improve the spatial and temporal scales that can be explored within a single nonlinear optical microscope platform. Here we demonstrate, for the first time to our knowledge, that it is possible to fabricate inexpensive masks using femtosecond laser micromachining that can be readily deployed within the multiphoton microscope architecture to transform the system from a traditional point-scanning system to SPIFI and gain the inherent advantages that follow.