Near-infrared laser irradiation of a multilayer agar-gel tissue phantom to induce thermal effect of traditional moxibustion

Traditional moxibustion therapy can stimulate heat and blood-vessel expansion and advance blood circulation.In the present study,a novel noncontact-type thermal therapeutic system was developed using a near-infrared laser diode.The device allows direct interaction of infrared laser light with the skin,thereby facilitating a controlled temperature distribution on the skin and the deep tissues below the skin.While using a tissue-mimicking phantom as a substitute for real skin,the most important optical and thermal parameters are the absorption/attenuation coefficient,thermal conductivity,and specic heat.We found that these parameters can be manipulated by varying the agar-gel concentration.Hence,a multilayer tissue-mimicking phantom was fabricated using different agar-gel concentrations.Thermal imaging and thermocouples were used to measure the temperature distribution inside the phantom during laser irradiation.The temperature increased with the increase in the agar-gel concentration and reached a maximum value under the tissue phantom surface.To induce a similar thermal effect of moxibustion therapy,controlled laser-irradiation parameters such as output power,wavelength and pulse width were obtained from further analysis of the temperature distribution.From the known optothermal properties of the patient's skin,the temperature distribution inside the tissue was manipulated by optimizing the laser parameters.This study can contribute to patient-specic thermal therapy in clinics.

Preparation of entangled states of atomic qubits via atom-cavity-laser interaction

We propose a scheme to prepare the Bell states for atomic qubits trapped in separate optical cavities via atom-cavity-laser interaction.The quantum information of each qubit is encoded on the degenerate ground states of the atom,so the entanglement between them is relatively stable against spontaneous emission.The proposed scheme consists of a Mach-Zehnder interferometer（MZI） with two arms,and each arm contains a cavity with an N-type atom in it.It requires two classical fields and a single-photon source. By controlling the sequence and time of atom-cavity-laser interaction,the deterministic production of the atomic Bell states is shown.We also introduce the generalization of the present scheme to generate the 2N-atom Greenberger-Horne-Zeilinger state.

Research of cornea section's shape ablated by 193-nm ArF laser spots

The ablation theory of cornea and biology effect by 193-nm ArF excimer laser axe introduced. The ablation tracks model is put forward to make laser spots scan axound cornea by many steps and many areas to change cornea curvature. The corneal average ablation curve is calculated by software so as to explain the feasibility of the ablation tracks model. By analyzing the actual ablation shapes of many axbitrary cornea sections, the optimal ablation method for deciding the random position of every laser spot in every ablation track is obtained. Experiments combining the ablation model with the device testify the energy stability of laser spots and the accuracy of rectifying anisometropia.