用于原子与通信波段激光器调谐及控制研究

发布时间：2018-04-04 07:30

本文选题：连续调谐　切入点：钛宝石激光器　出处：《山西大学》2013年博士论文

【摘要】：全固态连续单频可调谐激光器,具有输出光谱范围宽、输出功率高、使用方便、窄线宽及全固态等优点,因此在高灵敏度的干涉仪、高分辨率激光光谱、引力波探测、量子通讯、原子冷却及其它基础物理研究等领域获得了广泛应用。作为可调谐激光器中的代表——全固态连续调谐单频钛宝石激光器由于它频谱范围宽,线宽窄,相位噪声低,功率高,等独特的优点,已成为量子通讯、量子信息处理、激光光谱等领域的重要光源。鉴于全固态连续单频可调谐钛宝石激光器在我们实验室和其它科研领域有着广泛的应用前景,为了推动我们实验室基础研究和应用研究的发展,加快我们国家自主创新的步伐,我们分别对双折射滤光片组的设计、腔内标准具的锁定、锁定标准具需要的低噪声高压放大器、以及对作为泵浦源的高功率绿光激光器的控制系统设计等进行了一系列研究工作： 1、设计了一个可调谐的高功率低噪声单频绿光激光器。激光器采用LD端面泵浦技术,谐振腔采用四镜8字环形谐振腔结构,通过在谐振腔内插入楔形的复合Nd:YVO4增益晶体,倍频晶体LBO,光学单向器,在LD泵浦功率为47W时,获得了输出功率为10.7W的连续单频绿光激光输出,3小时的功率稳定性优于±0.64%,在此基础上,通过改变标准具的工作温度,实现了激光器的频率调谐,在温度改变约14℃时,激光器基频光的频率调谐范围达到了12GHz,相应倍频光的调谐范围为24GHz,由于调谐范围覆盖了碘分子多条吸收线,因此它可在基于碘分子超精细吸收峰的光频标系统中,提供优质的激光光源。2、设计制做了LOCK-IN、标准具探测器以及振镜电机控制信号等关键电子设备,实现了标准具与激光器腔内振荡光的锁定,为进行激光器连续调谐工作研究创造了条件。使用垂直入射TGG+半波片的光学单向器,进行连续调谐实验,发现了TGG晶体和半波片对连续调谐的影响,设计了布氏角入射TGG晶体及自然旋光补偿片的光学单向器。并总结出设计自然旋光补偿片时如何考虑s光反射的问题,以避免出现过补偿,为以后的实验设计工作积累了经验。在采用布氏角入射TGG+自然旋光补偿片结构的光学单向器进行的连续调谐实验中,最终实现了连续调谐20GHz的实验结果。由于钛宝石激光器有较宽的波长调谐范围,其中780nm光波恰好对应于铷原子跃迁线F3/2一F1/2,因此可以有效俘获铷原子并将之冷却。同时,利用波长为780nnm激光作为泵浦光,通过OPO技术还可获得1560nm纠缠源,可用于量子保密通讯研究。因此可以为铷原子的研究以及量子光学通讯提供优质光源。 3、设计完成了由单片机控制的LD泵浦源控制系统,与我所生产的10W单绿光单频激光器配套使用,达到了预期的效果。在此工作中设计完成了硬件PCB板的设计,并通过软件编程实现了预定的目标。系统开关机过程中实现了LBO倍频晶体温度自动均匀变化,在操作逻辑顺序上由程序控制,在运行过程中发现异常可自动进入关机程序,避免了许多人为误操作带来的安全隐患；在电流设置方面,由于程序设定了上限电流,操作过程不会出现过流损坏LD的情况；从而操作更方便,运行更安全。 4、设计完成了低噪声高压放大器的工作。通过设计电平搬移电路,将运算放大器输出电压搬移300多伏后,传递到末级放大作用的高压N沟道MOS管的栅源之间,使低电压的运算放大器与高压晶体管可以配合工作。经过两年多本所各实验室的使用,效果良好,满足了精密实验中低噪声放大的需求。在此基础上向国家知识产权局审请国家专利,并于2013年1月23日获得授权。创新性的工作： A.利用薄标准具温度变化实现大范围激光器频率调谐。 B.利用布氏角入射TGG+自然旋光补偿片避免了标准具效应对激光器连续调谐的影响。提出自然旋光补偿片过补偿及产生的原因,使补偿更加有效。 C.实现标准具与激光器频率的锁定,为研究连续调谐过程中的问题创造了条件。 D.利用单片机程序控制激光器泵浦源,使整个系统操作更加简便,运行更加可靠。 E.设计了电平搬移电路,实现在高压放大器中运算放大器输出信号下移300多伏驱动高压MOS晶体管。
[Abstract]:The full - solid continuous single - frequency tunable laser has the advantages of wide output spectrum range , high output power , convenient use , narrow line width and solid state and the like , and is widely applied in the fields of high - sensitivity interferometer , high - resolution laser spectrum , gravitational wave detection , quantum communication , atom cooling and other basic physical research .

As a representative _ all - solid - state continuous tuned single - frequency Ti - sapphire laser in tunable laser , it has become an important light source in quantum communication , quantum information processing and laser spectrum because of its wide spectral range , narrow line width , low phase noise , high power , and so on .

In view of the wide application prospect of the full - solid continuous single - frequency tunable Ti - sapphire laser in our laboratory and other scientific research fields , in order to promote the development of our laboratory basic research and application research , to accelerate the pace of our national independent innovation , we have carried out a series of research on the design of birefringent filter banks , the locking of etalon in the cavity , the low noise high - voltage amplifier required by the locking standard , and the design of the control system of the high - power green laser as pumping source .

1 . A tunable high - power low noise single - frequency green laser is designed . The laser adopts LD end - end pump technology . The resonant cavity adopts a four - mirror 8 - word ring resonator structure . The frequency tuning range of the laser is better than 卤 0.64 % by changing the operating temperature of the etalon .

In the continuous tuning experiment using the optical one - way device with a Bragg angle incident TGG + natural optical compensation plate structure , the experimental results of 20 GHz tuning are finally realized .

Because the Ti - sapphire laser has a wide wavelength tuning range , the 780 nm light wave exactly corresponds to the rubidium atom transition line F3 / 2 - F1 / 2 , so that the rubidium atom can be effectively trapped and cooled . At the same time , a 1560nm entangled source can be obtained by using a laser with a wavelength of 780 nnm as the pumping light , and can be used for quantum secret communication research . Therefore , the research on rubidium atoms and quantum optical communication can be provided for providing a high - quality light source .

3 . The LD pump source control system controlled by the single chip microcomputer is designed and finished . The design of the hardware PCB board is achieved . The design of the hardware PCB board is designed and realized by software programming . In the process of the system switching machine , the automatic uniform change of the temperature of the frequency doubling crystal is realized . In the operation logic sequence , the automatic uniform change of the frequency doubling crystal temperature can be realized , and the shutdown program can be automatically entered in the operation process , so that the potential safety hazard caused by misoperation is avoided ;
In the aspect of the current setting , since the program sets the upper limit current , the operation does not occur in the case of overcurrent damage LD ;
so that the operation is more convenient and the operation is safer .

4 . A low - noise high - voltage amplifier is designed and completed . By designing the level shift circuit , the output voltage of the operational amplifier is shifted by more than 300 volts , and then transferred to the gate source of the high - voltage N - channel MOS tube at the final stage amplifying effect , so that the low - voltage operational amplifier and the high - voltage transistor can work together .

After more than two years of use of various laboratories , the effect is good enough to meet the requirement of low noise amplification in the precision experiment . On this basis , the State patent is requested to the State Intellectual Property Office , and the authorization is granted on January 23 , 2013 .

Innovative work :

A . A wide range of laser frequency tuning is achieved with a thin etalon temperature variation .

B . The influence of etalon effect on the continuous tuning of the laser is avoided by using the Bragg angle incident TGG + natural optical compensation slice , and the reason of overcompensation and generation of the natural optical rotation compensation sheet is proposed , so that the compensation is more effective .

C . Achieving the locking of etalon and laser frequency creates conditions for studying the problems in the continuous tuning process .

and D . the laser pumping source is controlled by using a single - chip microcomputer program , so that the operation of the whole system is simpler , and the operation is more reliable .

E . A level shift circuit is designed to realize the operation of the amplifier output signal in the high voltage amplifier by more than 300 V to drive the high - voltage MOS transistor .

【学位授予单位】：山西大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TN248

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