|Substrate Material||Fused Silica (Quartz)|
|Nominal Focal Length||5.2 mm||6.7 mm||18.6 mm|
|Wavelength Range||300 - 1100 nm||400 - 900 nm||400 - 900 nm|
|Lenslet Grid Type||Square Grid|
|Lenslet Pitch||150 µm||300 µm|
|Lens Shape||Round, Plano-Convex Spherical||Square, Plano-Convex Parabolic|
|Fill Factor (Approximate)a||74.5%||100%|
|Lens Diameter||146 µm||300 µm|
|Chrome Apertures||Yes, around Microlenses||No|
|Array Size||10 mm x 10 mm x 1.2 mm|
|Mount Window Aperture|
(-M Versions Only)
|9 mm x 9 mm|
- 10 mm x 10 mm High-Quality Microlens Array
- Available Unmounted or in a Ø1" Mount
- Two Wavelength Ranges Available:
- 400 - 900 nm with an AR Coating
- 300 - 1100 nm with a Chrome Mask
- Fused Silica Substrate
- Square Grid Arrangement of Microlenses
- Arrays with 150 µm or 300 µm Lenset Pitches Available
- Near Diffraction-Limited Spot Size
- High Spot-to-Background Contrast
- Use for Custom-Built Shack-Hartmann Wavefront Sensors
These Fused Silica Microlens Arrays are available mounted or unmounted (click here to see an enlarged photo). Fused silica offers excellent transmission characteristics from the UV to the IR. The microlenses have a plano-convex shape and are arranged in a square grid with a lens pitch of 150 µm or 300 µm. The arrays with a pitch of 150 µm have round lenslets. The arrays with a pitch of 300 µm have square lensets, allowing for a fill factor of 100%.
The MLA150-5C lens array and its mounted counterpart have a chrome mask that blocks light from being transmitted through the spaces between microlenses, thereby increasing the constrast. The unmounted MLA150-7AR and MLA300-14AR lens arrays and their mounted versions have a broadband AR coating on both sides to reduce the surface reflections in the 400 - 900 nm spectral region to below 1%.
These lenses are formed using photolithographic techniques based on semiconductor processing technology, which allows for excellent uniformity in the shape and position of each microlens. Unlike some microlens arrays produced from molded epoxy, this method produces microlens arrays where the spot size of each microlens is nearly diffraction limited.
For the mounted versions, the microlens is glued into a Ø1", 3.5 mm thick mount plate that is compatible with all standard Ø1" optics mounts. The aperture of the lens window is 9 mm x 9 mm. Their unmounted couterparts are most easily held using one of our cylindrical lens mounts, which are specifically designed to hold square or rectangular optics.
A microlens array used in conjunction with a CCD array can constitute the core of a Shack-Hartmann wavefront sensor. As seen from the figure below, a planar wavefront that is transmitted through a microlens array and imaged on a CCD sensor will form a regular pattern of bright spots. If, however, the wavefront is distorted, the light imaged on the CCD sensor will consist of some regularly spaced spots mixed with displaced spots and missing spots. This information can be used to calculate the shape of the wavefront that was incident on the microlens array. Shack- Hartmann type wavefront sensors can be used to characterize the performance of optical systems. In addition, they are increasingly used in applications where real-time monitoring of the wavefront is used to control an adaptive optic with the intent of removing the wavefront distortion before creating an image.