Batop SAM 可饱和吸收体

内容９�/strong>

微芯片安裄�/p>

工作原理

脉冲能量Ep

重复率frep

脉冲宽度tp

微芯片安裄�/strong>

上图所示是的被动调Q的单片微片激光器由Nd掺杂YVO4激光晶体和可饱和吸收镜(SAM)粘合在一起组成。激光腔体长度L在区�?00��m..300��m主要由激光晶体厚度决定。典型掺Nd�?&�?%� 来自一个连续二极管激光的线性极�?08nm泵浦光平行面向c轴自动对焦激光晶体。激光晶体中的一个典型的泵浦光斑直径约为50��m-100��m�?064nm波长单模激光输出光脉冲是从分色镜中反射出、�/span>

微芯片的主要特性取决于以下参数９�/span>

脉冲能量Ep

重复率frep

脉冲宽度tp

工作原理

可饱和吸收体（SAM）作为被动调Q开关� 寸�span>波长�?064nm皃�span>激光来诳�/span>低强度非饱和SAM反射率在0.75-0.9的区域、�span>激光晶佒�/span>的连续泵浦上部将被填补直到获得足够大的自发辐射。然后SAM饱和＋�span>激光器发出一个强大的短脉冲� 在连续泵浦期间，发展重复，重复频率德国财务报告管理小组inceasing与泵浦功率密度接近线性关系。由于光能量的一部分是在SAM的吸收层消退，安排必须删除此芯片产生的热量。如果激光腔长度短，单模激光泵浦光斑直径小、�/p>

pulse energy E_p

_{According to the well established formalism (Journal of the Optical Society of America B� Vol. 16� Issue 3� pp. 376-388� 1999) of passive Q-switched microchip laser the pulse energy Epcan be estimated as follows:}

with

F_{sat，Lsaturation fluence of the laser material}

_{Apump spot area in the resonator}

_{��Rmodulation depth of the SAM}

_{Ttransmission of the output coupler}

_{Ansnon-saturable losses� mainly from SAM}

_{With typical values Fsat，L = 37.3 mJ/cm2� A = 1.3x10-5cm2 ( 40 ��m spot diameter)� ��R = 0.1� T = 0.1� and loss = 0.05 the pulse energy can be estimated to Ep ~ 32 nJ.}

_{repetition rate frep}

The average output power P_avis proportional to the pump power. Therefore the repetition rate shows a linear behavior by changing the pump power according to:

with

_{��s slope efficiency}

_{Pp pump power}

_{PP，thpump power threshold}

By changing the pump power P_Prepetition rates between 100 kHz and 2 MHz can be realized with a nearly constant pulse energy E_P. Because the pulses start with spontaneous emission� the repetition rate shows a time jitter of about 1 %� increasing with decreasing pump power and rate.

pulse duration t_P

The pulse duration t_Pin passive Q-switched lasers can be estimated by:

with

TR resonator round trip time

��R modulation depth of the SAM

n refractive index of the resonator material

L resonator length

c speed of light in vacuum.

With a short laser crystal length L = 0.2 mm� refractive index n ~ 1.95� and a SAM modulation depth of ��R = 0.1 the pulse duration is about 91 ps.