RESUMO
An extension of Nomarski differential interference contrast microscopy enables isotropic linear phase imaging through the combination of phase shifting, two directions of shear, and Fourier space integration using a modified spiral phase transform. We apply this method to simulated and experimentally acquired images of partially absorptive test objects. A direct comparison of the computationally determined phase to the true object phase demonstrates the capabilities of the method. Simulation results predict and confirm results obtained from experimentally acquired images.
Assuntos
Aumento da Imagem/instrumentação , Interpretação de Imagem Assistida por Computador/métodos , Microscopia de Contraste de Fase/instrumentação , Refratometria/instrumentação , Desenho Assistido por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/instrumentaçãoRESUMO
We introduce a quantitative phase imaging method for homogeneous objects with a bright field transmission microscope by using an amplitude mask and a digital processing algorithm. A known amplitude pattern is imaged on the sample plane containing a thick phase object by placing an amplitude mask in the field diaphragm of the microscope. The phase object distorts the amplitude pattern according to its optical path length (OPL) profile, and the distorted pattern is recorded in a CCD detector. A digital processing algorithm then estimates the object's quantitative OPL profile based on a closed form analytical solution, which is derived using a ray optics model for objects with small OPL gradients.
Assuntos
Algoritmos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Iluminação/métodos , Microscopia de Contraste de Fase/métodos , Processamento de Sinais Assistido por Computador , Microscopia de Contraste de Fase/instrumentação , Imagens de Fantasmas , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
We demonstrate polarization selective computer-generated holograms (PSCGH) for visible light operation fabricated in glass by a femtosecond laser. For this purpose we create arrays of tailored microwaveplates by controlling the laser formation of nanogratings embedded in fused silica. A birefringent cell-oriented encoding method adapted to the characteristics of the physical writing process is proposed and implemented. According to this method, each cell contains a micro-waveplate with controlled phase retardation and orientation. A detour of each microwaveplate, combined with the orientation of its principal optical axis, simultaneously realizes a different phase function for each polarization. PSCGH's are attractive for integration with other free-space and guided-wave devices embedded in glass.
