Flyer_Metrology

Characterization of micro and nano-optical elements with multiple wavelenghts interferometry

  • Responsible : Myunsik KIM, Toral SCHARF
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The high resolution interference microscopy (HRIM) allows characterization of amplitude and phase of electromagnetic wave-fields in the far-field. While the amplitude measurement is diffraction limited and has finite spatial resolution, the phase measurement is in principle not subjected to the resolution issues and super-resolution in phase field can be obtained. The HRIM is already proven as a useful tool for characterizations of micro-optical elements[1-4]. We work with three light source at red at 642nm, green at 532nm, and blue at 405nm wavelengths and measure phase and amplitude measurement by five frame phase shifting interferometry. Data can be collected in three-dimensional arrays by scanning in propagation direction with a piezo stage providing 500μm scan range.

Figure 1. Experimental setup of the RGB HRIM: (a) a picture of system and (b) a schematic of the basic configuration when 20μm diameter microlenses are illuminated with plane wave and spherical wave.

A highlight of our system is the possibility of working in immersion. In general, a rim of sphere or ball is hard to resolve with because of the limited numerical aperture of the optical system. Immersion fluid helps to resolve this problem and provides highest resolution. With such a system

Figure 2. Phase and intensity measurements of a micro-sphere at different focus position along the optical axis. Optical properties of object down to several micrometers can be characterized with such an approach.

Applications:

  • Micro-optical element testing: small size, high numerical aperture (NA) microlenses, and micro-sphere
  • Optical near-field component characterization: solid immersion lens (SIL)
  • Investigation and characterization of highly of focused beam

Actual Projects in this field:

SURPASS FP7-ICT-2007-2 No. 224226

References

  • [1] A. M. Raighne, et al. Rev. Sci. Instrum. 77 (2006).
  • [2] V. Paeder et al JEOS 2 (2007) 07005.
  • [3] P. Ferrand et al Opt. Express 16 (2008).
  • [4] C. Rockstuhl et al Current Nanoscience 2 (2006).