Dual-wavelength diffraction phase microscopy for simultaneous measurement of refractive index and thickness

作者：Jafarfard Mohammad Reza; Moon Sucbei; Tayebi Behnam; Kim Dug Young^*

来源：Optics Letters, 2014, 39(10): 2908-2911.

DOI：10.1364/OL.39.002908

We present a quantitative phase microscopy scheme that simultaneously acquires two phase images at different wavelengths. The simultaneous dual-wavelength measurement was performed with a diffraction phase microscope (DPM) based on a transmission grating and a spatial filter that form a common-path imaging interferometer. With a combined laser source that generates two-color light continuously, a different diffraction order of the grating was utilized for each wavelength component so that the dual-wavelength interference pattern could be distinguished by the distinct fringe frequencies. Our dual-wavelength phase imaging allowed us to extract information on the physical thickness and the refractive index for a specimen immersed in a highly dispersive surrounding medium. We found that our dual-wavelength DPM (DW-DPM) provides an accurate measurement of the volume and the refractive index of a microscopy sample with good measurement stability that results from the common-path geometry.

• 出版日期2014-5-15