Session:

Three dimensional holograms are formed using the optical holography technique. There have been reports on improved performance with Digital Holography and Incoherent Digital Holography. These advanced technologies focus on macroscopic scale holograms. External lasers and digital tools are required. In this report, we will focus on microscopic holographic effects using sub-7nm photonic CMOS transistors. Due to the resonance and coherent holographic process, there are more information in the photonic CMOS output signals, which makes wide-band optical computing a reality.

A hologram contains more information, because it is formed by interference / modulation of split coherent lights. A regular picture is produced by reflection of an incident light from an object. A hologram is produced by interference of an incidence light and its split coherent light affected by an object. As the result, the 3-D features are enhanced and delineated by holography. In some ways holography is similar to a Michaelson Interferometer.

If two lights are coherent, their phases are organized. If the two lights are incoherent, their phases are not related. Although incoherent digital holography has been demonstrated, more complicated setup would be required. In this paper only coherent holography will be presented.
A photonic CMOS transistor includes a laser in the drain area, and another laser in the source area, and photon sensors in the well region. When the MOSFET is on, the lasers and photon sensors are also on. When the MOSFET is off, all devices are off. The MOSFET, lasers, and photon sensors are fabricated as one integral transistor.

A resonance chamber is formed at the center of the CMOS transistor, when the source laser and the drain laser are coherent, and only the drain laser / sensor receives an input light signal. This creates a holographic effect in the resonance channel region. The output light signal will include the holographic messages, which can be transmitted to other transistors for optical processing. The performance is superior due to the more sophisticated interference and modulated split coherent lights.

The CMOS transistor is designed for only the drain laser and drain photon sensors to receive external light signals, as there is a depletion region located only at the drain side. External lights are blocked from the source laser.

We will present data examining the coherence vs. sub-7nm transistor parameters, such as Rch and Rds (channel and source drain resistance). For femtosecond pulsed lasers, we will look into the effects of frequency as a function of the quality of the coherent holographic signals. Device features, and process integration will be discussed for the micro holographic effects. How optical computing can be implemented, taking advantage of the nonlinear optoelectronic CMOS with micro holography will be presented.

The design of an optical processor relies on transmission of optical signals either through an micro optical waveguide or confined free space. Laser communications between photonic transistors in an optical computer become more efficient if the lights are encoded with micro holographic techniques. We will introduce a few examples of logic gate designs (AND, OR, NAND, NOR, XOR, Comparator, OP AMP) and SRAM for optical computing using micro holography.

Finally, we would like to discuss how to enhance the micro holographic effects using nonlinear optical materials in optical waveguides and photonic CMOS, from UV to NIR and Terahertz spectral ranges. The photonic CMOS needs to be configured with nonlinear optical materials, in order to adapt to such nonlinear micro holographic process. A few different approaches will be presented.

James Pan

Appearances