**4. Summary and conclusions**

*Nanorods and Nanocomposites*

**Figure 20.**

*band [9].*

**Figure 21.**

*the uncoated Si substrate [25].*

**88**

**Figure 22.**

*uncoated ZnSe lens, over the 8–10 μm spectral band [9].*

*Measured wavelength-dependent reflectance of uncoated and single-layer nanostructure AR-coated ZnSe lenses. The AR-coated ZnSe lens demonstrates an average reflectance of 0.6%, compared to 15.2% for the* 

*Measured wavelength-dependent reflectance of multilayer AR-coated and uncoated Si <211> wafers. The multilayer AR coating on Si <211> wafers offers significantly lower reflectance over the 3–5 μm MWIR spectral* 

*Measured LWIR wavelength-dependent reflectance of two-layer AR coating structure on Si <211> substrate with that for an uncoated substrate. The AR coating significantly reduces reflection over this range compared to* 

In this chapter we have first discussed recent efforts towards the design, modeling, and experimental development of next-generation carbon nanotube-based bolometers for IR sensing and imaging. The goal in the development and advancement of this technology is to enable high performance, high frame rate, uncooled microbolometers for MWIR and LWIR bands. We have presented recent results of growing variously orientated SWCNT and MWCNT films that demonstrate the promise of using CNTs for developing high performance and small pixel microbolometer arrays.

The growth and application of nanostructured layers for developing high quality antireflection coatings likewise offers an innovative approach for minimizing reflection losses in state-of-the-art sensors and optical windows for both defense and commercial applications. The step-graded multilayer antireflection technology has been shown to be both broadband and omnidirectional in nature. These nanostructure-based AR coatings have demonstrated high performance over spectral bands spanning the visible to the IR with the potential to include larger area substrates to benefit next-generation sensors.

Optical sensing technology is critical for various defense and commercial applications including optical communication and IR imaging. Advances in detector materials and technologies have been achieved over a broad spectrum using Si and SiO2 based nanostructures and novel carbon nanotube-based materials. These technological advances are opening doors for new approaches to apply device design methodologies that can offer enhanced performance and low-cost optical sensors and systems benefitting a wide range of infrared and electro-optical applications.
