A laser beam is an effective power and data carrier that offers inherent advantages in terms of the simultaneous transfer of wireless information and power, which is widely used in both the Internet of Things and the Internet of Energy. This paper proposes an adaptive high-power and high-efficiency laser-based simultaneous wireless information and power transfer system. This is achieved through the use of adjusted and modulated laser diode systems at the transmitter and multiplexed photovoltaic cells, a coupler, a filter, and a maximum power point tracking (MPPT) converter at the receiver. The interaction between the converter and the communication component is investigated theoretically and experimentally using a current-fed boost MPPT converter with the MPPT algorithm of perturbation and observation. The results indicate a maximum DC output power of 7.3 W at the receiver and a maximum MPPT converter efficiency of 84%. Additionally, at a data rate of 495 kbit/s, with a DC output power of 5.11 W, the bit error ratio is 2.62 × 10 ^-4 for the binary amplitude shift keying modulation format, the MPPT converter efficiency is 88%, and the corresponding loss of communication is about 1% of the total transmitted power.

Wireless laser power transmission is a promising technique in the far-field wireless power supply with the advantages of high-power density, and small transmitter and receiver sizes. This study proposes a high-efficiency pulse width modulation-based wireless laser power transmission step-down system based on an 808 nm laser diode and gallium arsenide photovoltaic cells. The output voltage of the proposed system is controlled with the use of pulse width modulation of laser diodes in the transmitter without switch tubes and rectifier diodes in the receiver. The model of the proposed system is built, and characteristics of the system is analyzed based on the state-space averaging method. Additionally, the steady and dynamic operations, as well as the efficiency analyses, are investigated and evaluated experimentally. With the use of the propounded system, when the load is 3 ohms and the output voltage is 1.5 V, a converter efficiency of 96.6% is obtained that is ~10% and ~5% higher than those of continuous wireless power transmission constant voltage systems with asynchronous and synchronous buck converters, respectively.

Mini-cameras are one of several emerging types of cat-eye devices using small lenses with insufficient retro-reflection for traditional detection systems to identify. Based on a structural analysis of these devices, this paper provides an accurate theoretical description of the received beam profile. The simulated and experimental results have good similarity in terms of profile shapes and trends with different incident angles and defocus distances. An analysis of the detection conditions and the reflection image features described in this article can thus be applied to hidden camera detection. Mini-cameras can be detected according to these features of the received beam profiles.