Diffraction Focal Position and Vector Diffraction Theory for Micro Holographic Storage Systems

• Published in: Applied sciences Vol. 4; no. 1; pp. 57 - 65
• Main Authors: Min, Cheol-Ki, Moon, Hyungbae, Kim, Do-Hyung, Park, No-Cheol, Park, Kyoung-Su, Park, Young-Pil
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.03.2014
• Subjects: Boundary conditions; Diffraction; diffraction efficiency; diffraction focus; Diffraction theory; Efficiency; Electric fields; Information storage; interferogram; Interferometers; Mathematical analysis; Mathematical models; microholographic storage system; polarization; Reading; refractive index modulation; scalar diffraction theory; Storage systems; vector diffraction theory; Vectors (mathematics); Wavelengths
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app4010057

In this study, we proposed a method to determine the optimal focal position for micro-holographic storage systems, using vector diffraction theory; the theory provides exact solutions when the numerical aperture (NA) exceeds 0.6. The best diffraction focus was determined by the position and wavelength corresponding to minimal spherical aberration. The calculated refractive index modulation, polarization illumination, and boundary conditions at the interface of different media were analyzed. From the results of our analysis, we could confirm the size of micrograting as a function of NA and wavelength, based on vector diffraction theory, compared with scalar diffraction theory which defines the micrograting by . To demonstrate our analysis, we adapted an optical alignment method using a Twyman-Green interferometer, and could obtain good agreement between analysis and experimental results.