Objective

Vendors must build a microstructure for dielectric optically-transparent materials to act as a narrowband (1030 to 1070nm), high-reflector for continuous wave laser light while maintaining high transmission in mid- and long-wave infrared spectrums.

Description

The Army needs highly reflective microstructures for the 1030 to 1070 nm range for CW laser light. This technology will protect equipment and allow for the uninterrupted operation of mid-wave to long-wave infrared sensors. Such microstructures will efficiently block the specified range of wavelengths while transmitting light throughout the rest of the infrared spectral region via strong optical-imaging quality.

The Small Business Technology Transfer Program wants to develop a microstructure that can etch onto a variety of dielectric optical materials whose transparency regions span the infrared (specifically ZnS, ZnSe, BaF2, Silicon, Ge, and other such optics). It should also reflect greater than 99.5% of 1030 to 1070 nm light while not reducing the transmission of the substrate by more than 10%. Additionally, it must maintain a strong optical-imaging quality (structural similarity index measure (SSIM) greater than 0.9) in the infrared spectral region.

The Army prefers a microstructure that can handle optical powers of up to 10 MW/cm2 with an acceptance angle of at least +/- 15 degrees over a one-inch clear aperture. Proposed microstructures should vidibly include an efficient mechanism for dissipating the absorbed or reflected optical energy at the specified wavelength range. Materials should not be limited to traditional optical materials. Instead, the Army encourages exploitation of compatible material platforms suitable for operation in the infrared spectral range.

Businesses must address the ability of the chosen material to dissipate the required optical power and operate under standard military specification. The proposed designs should be both polarization and vibration insensitive. Fabrication techniques needed to realize proposed filter designs should be clearly defined in the Phase I effort. Such structures should be scalable for dielectric optics with a diameter up to 5 inches.

Nano-structure resonant surfaces, a type of microstructure, consist of an array of index variations formed by holes or mesas. Typically, the array is etched into a substrate such as fused silica. Then, it’s conformally coated with a thin layer of higher-index material like aluminum oxide or tantalum pentoxide. This gives a high, low-index contrast and periodic variation in a direction transverse to the beam propagation direction.

In this way, you can set up a filter function in a single structured surface that performs as well as the 50 to 200 thin-film layers typical of an interference filter. Interference Filters accumulate their resonance in the longitudinal direction. This is one of the major advantages of nano-structure resonant reflection (notch transmission) filters.

Such CW microstructures can help commercial applications that use 1030 to 1070nm lasers for manufacturing as well as other industrial applications where protection of the operator and the environment is required to avoid damage from high intensity laser radiation. The CW, high reflector microstructure filters will provide uninterrupted, enhanced-force protection and day/night situational awareness. There exist numerous military applications for this technology at the Controlled Unclassified Information level and higher.

Phase I

The business must design, analyze and fabricate a CW, high-reflector microstructure for dielectric optical materials. It must reflect greater than 99.5% of 1030 to 1070 nm light while not reducing the transmission of the unaltered substrate in the rest of the MWIR and LWIR (3 µm to 12 µm) spectral regions by more than 10%. It also cannot significantly degrade the optical quality of the transmitted light (SSIM greater than 0.9).

The Army prefers a microstructure that can handle optical power densities up to 10 MW/cm2 with an acceptance angle of ± 10 degrees over a one-inch clear aperture. These filters should be both polarization and vibration insensitive. The deliverables shall include a detailed design for a high reflector microstructure on four of the substrate materials (zinc selenide, and three of the following: zinc sulfide, barium fluoride, silicon, and germanium).

Vendors must include the simulation results of the transmittance and reflectance spectra spanning the full spectral range (400 nm through 12 µm) along with a prototype coupon, i.e. a small-scale device 1-in-2 or larger with full functionality, as a proof of concept that demonstrates critical aspects of the manufacturing and clearly demonstrates the capability to actualize the proposed reflectors.

Phase II

Vendors must fabricate and demonstrate the prototype’s CW, high-reflector microstructures with a 2-inch clear aperture (but scalable up to a 4 inch clear aperture). The technology must show an acceptance angle of ± 15 degrees on four of the substrate materials (including ZnSe).

The filter needs to reject greater than 99.5% of 1030 to 1070 nm continuous-wave light while not reducing the transmission in the rest of the 3 µm to 12 µm spectral region by more than 10%. It must also not significantly degrade the optical quality of the transmitted light (SSIM greater than 0.9). Additionally, the reflectance should be polarization insensitive.

They should also handle optical power densities up to 10 MW/cm2. Vendors will conduct damage testing at the U.S. Army Research Laboratory with a 200 µm to 900 µm beam spot size. The Army expects at least four fully-operational prototypes with CW, high-reflector microstructures on four different materials covering the spectral range of 3 µm to 12 µm. The Army will test deliverables’ CW damage threshold and within sensor systems. The vendor must identify potential commercial and military transition partners for a Phase III effort.

Phase III

The Army will direct further research and development during Phase III efforts towards a final deployable design. It will incorporate design modifications based on the test results conducted during Phase II. The vendor must improve the engineering/form-factors, equipment hardening and manufacturability of the designs to meet the U.S. Army CONOPS and end-user requirements. The Army will integrate manufactured CW, high-reflector microstructures into relevant systems.

Potential commercial applications include the protection of thermal cameras for private security. The Army will also explore the possibility of incorporating these structures onto other glasses for the potential protection of any infrared systems.

Submission Information

All eligible businesses must submit proposals by noon ET.

To view full solicitation details, click here.

For more information, and to submit your full proposal package, visit the DSIP Portal.

STTR Help Desk: usarmy.rtp.devcom-arl.mbx.sttr-pmo@army.mil