Interferometric Optics

N-Slit Laser Interferometer

Interferometric Optics introduces its N-Slit Laser Interferometer (NSLI) applicable to:
  • Assessment of transmission gratings and optical surfaces
  • Detection of clear air turbulence (CAT)
  • Interferometric imaging
  • Interferometric microdensitometry
  • Interferometric microscopy
  • N-slit interference
  • N-slit interferometry
  • Secure interferometric communications
Based on multiple-prism beam expansion and digital detection the N-slit interferometer allows for the rapid interferometric characterization of transmission optical surfaces in general. A significant advance over traditional point-by-point incoherent microdensitometers and point-by-point incoherent microscopes. Specifications are given in [PDF].

Specific applications include the rapid characterization of:
  • Arrays of micro holes and/or micro nozzles
  • Biomedical and organic molecular arrays
  • Crystalline surfaces
  • Molecular, and digital, imaging surfaces
  • Optical surfaces
  • Textiles
  • Transmission gratings
Spatial resolution depends on the selected CCD or CMOS detector. As explained in the references, the resolution provided by the detector array can be enhanced, via quantum interferometric calculations, into the submicrometer or nanometer regime thus making the transition from microscope to nanoscope.


  • F. J. Duarte, T. S. Taylor, A. M. Black, and I. E. Olivares, Diffractive patterns superimposed over propagating N-slit interferograms, J. Mod. Opt. 60, 136-140 (2013).

  • F. J. Duarte, T. S. Taylor, A. M. Black, W. E. Davenport, and P. G. Varmette, N-slit interferometer for secure free-space optical communications: 527 m intra interferometric path length , J. Opt. 13, 035710 (2011).

  • F. J. Duarte, T. S. Taylor, A. B. Clark, and W. E. Davenport, The N-slit interferometer: an extended configuration, J. Opt. 12, 015705 (2010).

  • F. J. Duarte, Interferometric imaging, in Tunable Laser Applications, 2nd Edition, F. J. Duarte (Ed.) (CRC, New York, 2009) Chapter 12.

  • F. J. Duarte, Secure interferometric communications in free space: enhanced sensitivity for propagation in the metre range, J. Opt. A: Pure Appl. Opt. 7, 73-75 (2005).

  • F. J. Duarte, Comment on "Reflection, refraction, and multislit interference," Eur. J. Phys. 25, L57-L58 (2004).

  • F. J. Duarte, Tunable Laser Optics (CRC, New York, 2015) Chapter 2.

  • F. J. Duarte, Secure interferometric communications in free space, Opt. Commun. 205, 313-319 (2002).

  • F. J. Duarte, Interference of two independent sources, Am. J. Phys. 66, 662-663 (1998).

  • F. J. Duarte, Interference, diffraction, and refraction, via Dirac's notation, Am. J. Phys. 65, 637-640 (1997).

  • F. J. Duarte, Interferometric imaging, in Tunable Laser Applications, F. J. Duarte (Ed.) (Marcel-Dekker, New York, 1995) Chapter 5.

  • F. J. Duarte, On a generalized interference equation and interferometric measurements, Opt. Commun. 103, 8-14 (1993).

  • F. J. Duarte, Electro-optical interferometric microdensitometer system, US Patent 5255069 (1993).

  • F. J. Duarte, Dispersive dye lasers, in High Power Dye Lasers, F. J. Duarte (Ed.) (Springer-Verlag, Berlin, 1991) Chapter 2.

  • F. J. Duarte and D. J. Paine, Quantum mechanical description of N-slit interference phenomena, in Proceedings of the International Conference on Lasers '88, R. C. Sze and F. J. Duarte (Eds.) (STS, McLean, Va, 1989) pp. 42-47.

  • F. J. Duarte, Beam shaping with telescopes and multiple-prism beam expanders, J. Opt. Soc. Am. A 4, P30 (1987).


Published on the 13th of September, 2009; updated on the 11th of January, 2024.