Geometric Phase Lens

What is a Geometric Phase Lens?

A Geometric Phase Lens (GP Lens) is an LCP-based thin-film that functions like a volume lens or lens array, but with special features. (Polarization Directed Flat Lens)

How It Works

The desired lens phase profile is encoded directly into the local orientation of the optical axis. Circularly polarized light takes on this phase profile directly through the geometric phase (also called the Pancharatnam-Berry phase) effect.



Traditional Lens

  • 5-6mm Thick
  • 4-6g Weight
  • Multiple Aberrations
  • Primary Focus Only

ImagineOptix GPL

  • < 0.5mm Thick
  • < 1g Weight
  • Aberration Free
  • Primary and Conjugate Focus

Technical Details

Specifications

  • Typical Transmittance: 95-99%
  • Phase precision: As low as 0.02 mrad/µm
  • Available F-numbers: F/1.0 – F/100+
    • For IR, minimum F-number is F/0.5
  • Smallest Grating Period: <2um at edge
  • Typical Bandwidths (narrowband type): ±6% around 1550nm, 800nm, 633nm, 532nm, or 455nm; other wavelengths custom
  • Typical Bandwidths (broadband type): 450-650nm, 500-900nm, 1-4 µm; other wavelength ranges custom
  • Size: Up to 120 x 120mm sq
    • Round or arbitrary cut samples are custom
  • GPL Arrays
    • Minimum Lenslet Size: 15 µm
    • 1um transition region between lenses
  • Patterning: Any lens/array shape possible
  • Larger custom lens sizes are available with additional NRE

Benefits

Because of their unique phase manipulation mechanism and radically different fabrication, GP Lenses offer:

  • Effectively spherical wavefront, without aberration
  • Aspherical and cylindrical wavefronts, without aberration
  • Precision wavefront compensation of other elements
  • Ultra-low loss
  • Low F-numbers available
  • Thickness is largely independent of lens F/# and size
  • High transmission across visible or infrared wavelengths
  • Polarization dependent, with a positive or negative focal length controlled by the input polarization
  • Chromatic dispersion inverse to refractive lenses, allowing convenient compensation

Polarization Directed Flat Lenses

  • Unique Flat Lens Design
  • Polarization Dependent Focal Length
  • Excellent Transmission from 450 – 650nm

Polarization Directed Flat Lenses are flat lenses formed with polymerized liquid crystal thin-films that create a focal length that is dependent on polarization state. These unique lenses will have either a positive or negative focal length depending on the phase of the input polarization. With right handed circularly polarized light, the lenses will produce one focal length, while left handed circularly polarized light will present a focal length with the opposite sign. Unpolarized light will produce a positive and negative focal length at the same time. Both output waves are circularly polarized and orthogonal to each other. These Polarization Directed Flat Lenses are approximately 0.45mm thick, effectively simulating an ideal thin lens and are free from spherical aberration.

Buy from our partnered retailer Edmund Optics

  • Additional Information

    GP Lenses can be used in combination with refractive lenses, for ultra compact systems, and/or for chromatic aberration correction.

    Complex phase profiles can be made, much more easily than traditional diamond turning.

    Microlens arrays may be square, rectangular, or hexagonal, and lenslets may have radically different focal lengths.

    While transmission GP Lenses are most common, they can instead be made on mirrored substrates achieving reflective –mode.

    Principle:

    • Structure is nonlinear orientation angle
    • Phase = 
    • Phase can be aspheric, aberration corrected, or any function
    • Polarization selects ± focal length

    • Broadband
    • Real transmittance into Obj + Conj beams ~99% !
    • If RHC input, all is focusing 99.4%
    • If LHC input, all is diverging 99.2%
    • If other, both waves are present

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