Many storage and processing systems based on spectral holeburning have been proposed that access the broad bandwidth and high dynamic range of spatial-spectral materials, but only recently have practical systems been developed that exceed the performance and functional capabilities of electronic devices. This paper reviews the history of the proposed applications of spectral holeburning and spatial-spectral materials, from frequency domain optical memory to microwave photonic signal processing systems. The recent results of a 20 GHz bandwidth high performance spectrum monitoring system with the additional capability of broadband direction finding demonstrates the potential for spatial-spectral systems to be the practical choice for solving demanding signal processing problems in the near future.

A theoretical analysis and experimental verification of the sensitivity limits of frequency-modulated continuous-wave (FMCW) ladar in the limit of a strong local oscillator is presented. The single-photon sensitivity of coherent heterodyne detection in this shot-noise dominated limit is verified to extend to linearly chirped waveforms. An information theoretic analysis is presented to estimate the information efficiency of received photons for the task of locating the range to single and multiple targets. It is found that the optimum receive signal level is proportional to the logarithm of the number of resolvable range locations and the maximum theoretical photon information efficiency for FMCW ranging with coherent fields is log(e)≈1.44 bits per received photon.

A broadband signal analyzer that can determine the power spectra and direction of all spectrally nonoverlapping emitters for a two antenna system is proposed and demonstrated. A spectrum analyzer (SA) based on spatialspectral (S2) materials has previously been demonstrated that can monitor broadband signals (over several tens of gigahertz (GHz)) with sub-megahertz (MHz) resolution in real-time (submillisecond updates). Here, a dual-channel S2 SA is used to monitor the two outputs of a dual-drive dual-port optical Mach-Zehnder interferometer, where the RF inputs to the interferometer are driven by microwave signals with various time delayed components, emulating the outputs of a twoelement antenna array receiving signals from emitters with various bandwidths, formats, and center frequencies. The sensitivity of the optical power spectra of the two output ports to the time delay of each resolvable frequency component of the signals enables the determination of energy and direction of each resolvable frequency component of multiple emitters. A simple post-processing technique is used to estimate the angle of arrival (AoA) and power spectrum of each emitter. The interferometric technique works on a variety of signals including short bursts of variable bandwidth frequency agile microwave signals. The system's direction finding (DF) and SA capabilities enable it to simultaneously monitor multiple types of emitters. With the current system architecture, tone bursts, spread-spectrum waveforms, and chirped waveforms over 5 GHz of bandwidth were demonstrated. Sub-picosecond resolution (sub-0.5 degree angular resolution on bore-site for signals with a 3.8 GHz carrier frequency) was demonstrated for signals with a 19 dB signal-to-noise ratio (SNR) at 1 MHz spectral resolution. The theoretical and measured resolutions are shown to be in good agreement.

We describe the background and rationale for a new freshman course incorporating construction and testing of a small mobile robot. The custom robot kit is assembled in stages as the novice students learn basic electrical principles, the terminal characteristics of circuit components, and the basic practical skills necessary to build and test a printed circuit board. In this paper we explain the risks and difficulties overcome during the course development, the features and capabilities of the custom robot kits, and the assessment results for our first group of 90 students during the Fall 2004 semester. This effort is supported by an Educational Enhancement Award from the Montana Space Grant Consortium.

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