Abstract
Consumer cameras in the megapixel range are ubiquitous, but the improvement of them is hindered by the poor performance and high cost of traditional photodetectors. Graphene, a two-dimensional micro-/nano-material, recently has exhibited exceptional properties as a sensing element in a photodetector over traditional materials. However, it is difficult to fabricate a large-scale array of graphene photodetectors to replace the traditional photodetector array. To take full advantage of the unique characteristics of the graphene photodetector, in this study we integrated a graphene photodetector in a single-pixel camera based on compressive sensing. To begin with, we introduced a method called laser scribing for fabrication the graphene. It produces the graphene components in arbitrary patterns more quickly without photoresist contamination as do traditional methods. Next, we proposed a system for calibrating the optoelectrical properties of micro/nano photodetectors based on a digital micromirror device (DMD), which changes the light intensity by controlling the number of individual micromirrors positioned at + 12°. The calibration sensitivity is driven by the sum of all micromirrors of the DMD and can be as high as 10(-5)A/W. Finally, the single-pixel camera integrated with one graphene photodetector was used to recover a static image to demonstrate the feasibility of the single-pixel imaging system with the graphene photodetector. A high-resolution image can be recovered with the camera at a sampling rate much less than Nyquist rate. The study was the first demonstration for ever record of a macroscopic camera with a graphene photodetector. The camera has the potential for high-speed and high-resolution imaging at much less cost than traditional megapixel cameras.
Highlights
As an extension of human vision, digital consumer cameras in the megapixel range have become ubiquitous owing to the dramatic improvement of photodetector technology using planar materials as a sensing element
We propose a single-pixel camera integrated with a graphene photodetector based on compressive sensing (CS)
To solve the last problem mentioned above, i.e., accurate calibration, we propose a calibration strategy and system based on a digital micromirror device (DMD)
Summary
As an extension of human vision, digital consumer cameras in the megapixel range have become ubiquitous owing to the dramatic improvement of photodetector technology using planar materials as a sensing element. The large-scale array of photodetector comprising CCD or CMOS has been successfully manufactured and integrated into conventional cameras for high-resolution imaging. Its electronic structure has properties superior to those of conventional semiconductor materials, such as room-temperature in-plane carrier mobility up to 1.5 × 104 cm2/(V*s) [4], and it has a strong photo response near metal-graphene interfaces [5, 6] These excellent electronic properties and the high optical transmittance provide graphene a great potential for development in photodetectors [7]. The single-pixel camera, with its simple and inexpensive hardware structure and one photodetector, can recover high-resolution images using smaller sampling rate than the Nyquist rate. The surface of the GO is very wrinkly, as shown in 2(c), and the GO film is considered an insulator [11]
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