RESUMO
A high-quality black phosphorus (BP) saturable-absorber mirror (SAM) was successfully fabricated with the multi-layered BP, prepared by liquid-phase exfoliation (LPE) method. The modulation depth and saturation power intensity of BP absorber were measured to be 10.7% and 0.96 MW/cm(2), respectively. Using the BP-SAM, we experimentally demonstrated the mid-infrared (mid-IR) pulse generation from a BP Q-switched Cr:ZnSe laser for the first time to our best knowledge. Stable Q-switched pulse as short as 189 ns with an average output power of 36 mW was realized at 2.4 µm, corresponding to a repetition rate of 176 kHz and a single pulse energy of 205 nJ. Our work sufficiently validated that multi-layer BP could be used as an optical modulator for mid-IR pulse laser sources.
RESUMO
This paper proposes the concept of low dimensional optical beam and operator. In low dimensional space, beam (or operator) is decomposed into a limited number of orthogonalized low dimensional beams (or operators) through the singular value decomposition. It is possible to generate an unconventional beam by these low dimensional beams. Low dimensional operator allows independent operation of orthogonal dimensions which may produce greater freedoms. Storage space and computation resource are saved dramatically by using this method. Experimental realization of this scheme is briefly discussed at the end.
RESUMO
Adolescent idiopathic scoliosis (AIS) is a common disease with the age of 10 to 18 years, the Cobb angle more than 10 ° on the coronal plane and combined with the rotation of the vertebral body without other organic lesions. The disease can lead to deformity, pain and even damage of cardiopulmonary function, which seriously affects the physical and mental health and quality of life of patients. For mild to moderate AIS patients, regular observation, braces and other conservative treatment methods can effectively delay the progress of scoliosis. For AIS patients whose conservative treatment is ineffective and reaches the surgical threshold, surgery is recommended. Currently, the prevalent surgical method is posterior vertebral body fusion represented by the pedicle screw internal fixation system, which can often achieve good clinical efficacy. In recent years, Physical Therapeutic Scoliosis Specific Exercise (PSSE) has become more and more popular because of its safety and effectiveness. At present, the specific indications for the treatment of AIS patients are gradually improving, the concept and technology of treatment are constantly updated, and the clinical efficacy is constantly improved. This article will start from two aspects of conservative treatment and surgical treatment, mainly describes the commonly used treatment methods in clinical progress and application as well as the problems faced, in order to provide a reference for the selection of clinical treatment.