Products:
Nanopatterned Diffraction Gratings
Flat Focusing Gratings for laser locking
LightSmyth Technologies’ family of flat-substrate focusing gratings are designed for use with external-cavity lasers. The gratings focus optical input signals while simultaneously spectrally dispersing them. The focusing function is incorporated into the gratings via holographic design principles using curved and variably-spaced grating lines. Integrating focus function with spectral dispersion through holography rather than by use of curved substrates or lenses reduces system component count and facilitates miniaturization. Flat-substrate focusing gratings are also relevant to a broad range of applications in spectroscopy and general photonics.
LightSmyth flat-substrate focusing gratings are optimized for implementation in external-cavity diode laser (ECDL) systems where they provide frequency-selective feedback and thus laser frequency stabilization and linewidth narrowing. The gratings are designed for ECDLs employing the Littrow configuration and focus the first-order diffracted beam back toward the laser providing tunable locking feedback. Grating focal lengths are short (3.75 mm) in order to facilitate large longitudinal mode spacing and to enable convenient wide-range single-mode tuning.
Grating groove depth and duty cycle are optimized to provide maximal diffraction efficiency. Each grating is a master, free from replication flaws. Grating surfaces are cleanable and abrasion-resistant.
Array of flat-focusing gratings |
Schematic of grating lines
|
For additional technical information click here.
Standard Flat-Substrate Focusing Gratings
| Design Wavelength |
Design
Input Polarization1 |
Incidence Angle1 φ |
Approx. Line Density2 (l/mm) |
Size 1 (w × h) |
Part number* |
|---|---|---|---|---|---|
| 405 nm | s | 40 ° | 3175 | 6 mm × 3 mm | SCG-405S-0603A-X |
| 405 nm | p | 45 ° | 3640 | 3 mm × 6 mm | SCG-405P-0306A-X |
| 635 nm | s | 40 ° | 2028 | 6 mm × 3 mm | SCG-635S-0603A-X |
| 635 nm | p | 65 ° | 2857 | 3 mm × 6 mm | SCG-635P-0603A-X |
| 780 nm | s | 30 ° | 1282 | 6 mm × 3 mm | SCG-780S-0603A-X |
| 780 nm | p | 60 ° | 2222 | 3 mm × 6 mm | SCG-780P-0306A-X |
| 1310 nm | p | 30 ° | 763 | 6 mm × 6 mm | SCG-1310P-0606A-X |
| 1550 nm | p | 30 ° | 645 | 6 mm × 6 mm | SCG-1550P-0606A-X |
*In the part number X refers to the coating and X=Si, Al, AlM, and Au for bare silicon, bare Aluminum, Aluminum + MgF2, and gold respectively, and must be replaced with the appropriate symbol. Bare Silicon and Al + MgF2 are standard. Other coatings available at additional charge.
Note: The focal length of all gratings is 3.75 mm. All gratings are designed to provide laser feedback via the first diffraction order. The working distance between grating and laser diode front facet is d = 7.5 mm for all gratings. Silicon substrate has a thickness of 0.73mm. Substrate height and width tolerances are ± 0.3 mm.
1 See Figure 1 for design layout and illustration of parameters.
2 At grating midpoint.
Figure 1a. Schematic illustrating grating layout for s-input polarization (parallel to the grating lines). d, working distance, h, grating height, w, grating width.
|
Figure1b. Schematic illustrating grating layout for p-input polarization (polarization perpendicular to grating lines). d, working distance, h, grating height, w, grating width.
|
Pricing Information*
| Quantity | Price | |
|---|---|---|
| 405S, 405P, 635S, 635P, 780P | 780S, 1310P, 1550P | |
| 1 | $ 69 | available soon |
| 2 - 5 | $ 66 | |
| 6 – 10 | $ 63 | |
| 11 + | call | |
* Academic discounts are available to eligible institutions. To determine eligibility complete an account application procedure.
Custom Silicon Focusing Gratings
Our optical engineers will be happy to discuss a custom flat-substrate focusing grating solution for your specific application. Our general capabilities are:
- up to 12-inch diameter substrates
- up to 7000 lines/mm line density
- variable duty cycle
- arbitrary line curvature
- line widths as thin as 100 nm
- groove depths up to 400 nm.