Flame locking of dye lasers to atom lines

Frequency locking of N₂-laser-pumped, flash-pumped and continuous-wave dye lasers near the non-inverted 3S-3P Na atom transitions is obtained by placing sodium vapor produced in a flame inside the untuned dye laser cavity. Several possible causes for the spectral condensation of the dye emission are suggested.     

Single mode operation of a narrow bandwidth dye laser using a single prism, grazing incidence grating long cavity

The single mode pulsed dye laser is an attractive tool for many spectroscopic applications. Long cavity tunable dye lasers generally operate in multi-longitudinal modes within the bandwidth of gain profile. Single longitudinal mode oscillation can be obtained by either making the cavity short enough or introducing an additional loss mechanism, in which all modes but one have a gain less than their loss. A new technique to achieve single mode operation in a long cavity dye laser, based on Rhodamine 6G dye in ethanol and ethylene glycol solution, pumped by a high repetition rate copper vapor laser, is reported. This laser, which operates in three modes in grazing incidence grating configuration (cavity length of 16 cm), has been made to lase in single mode by increasing the loss in the resonator through beam walk-off.     

CW dye laser operation at 200 W pump power

A continuously operating jet stream dye laser was pumped by a multiwavelength-multimode argon-ion-laser with a pump power up to 200 W. Rhodamine 6G-chloride was dissolved in a water-polyvinylalcohol-ammonyx solution. The dye laser was prism-tunable between 560 and 650 nm with maximum output power at 600 nm. The maximum output power of the cw dye laser was 43 W without tuning element and 33 W with a prism placed inside the cavity. Operation of a jet stream dye laser with a pump power higher than 200 W and an efficiency of about 30% seems to be possible.     

Cylindrical microcavity laser based on the evanescent-wave-coupled gain

A microcavity laser based on the gain only in the evanescent field region of whispering gallery modes has been demonstrated. A cylindrical microcavity of 125 microm diam was surrounded by rhodamine 6G dye molecules in an ethanol solution of lower refractive index such that whispering gallery modes of the microcavity underwent laser oscillation when the dye molecules in the evanescent field region outside the cavity were excited by a second harmonic of a Nd:YAG laser. For particular pumping spots, single-mode laser oscillation of a transverse magnetic mode was observed at about 600 nm with associated cavity Q of 3x10(7).     

Laser a colorant pompe longitudinalement emettant a deux longueurs d'onde accordables

A technique is reported which allows a longitudinally pumped dye laser to operate simultaneously at two wavelengths. This is done by inserting in the cavity a prism, positioned at a very high angle of incidence, to separate the two wavelenghts. An intra-cavity Glan prism with an open escape window is used to separate the pump beam and the stimulated emission.     

A prism anamorphic system for Gaussian beam expander

Basic properties are given of the prism anamorphic expander of a Gaussian beam composed of a couple of prisms in tandem. Its shorter overall length for a given expansion, relative ease of optical adjustment, a sharp selection of polarization component, and rather small inclusive dispersion make it an excellent beam expander in a specific laser cavity. The design principle is presented of the prism system with a grating for an anastigmatic optical resonator for a dye laser of narrow linewidth and of short pulse duration.     

A mirror-free cavity configuration for a CW ring dye laser

A new cavity configuration without mirrors is described for a CW ring dye laser. The cavity design is based on a new type of focusing prism which uses the Brewster angle of incidence and total internal reflection. Special roof prisms allow wavelength tuning. All of these elements are made from uncoated quartz thus allowing dye laser operation over a large range of wavelengths. CW operation as well as synchronously pumped mode locked operation with intracavity doubling is reported using the Rhodamine 6G dye.     

Detection and Quantitation Of Several Atomic Species By Intra-cavity Quenching Of Laser Emission

Until recently laser research has been the province of the physicist wherein lasers have been utilized extensively as sources of coherent, highly monochromatic energy. The thrust of this research has been to employ the organic solution laser output as an analytical signal from which information about a particular system may be extracted. Preliminary investigations in this laboratory showed that a great number of variables are active in the achievement of lasing from an organic solution. More significantly, concurrent work in this laboratory produced some anomalous results which were subsequently attributed to a cavity defect. This suggested that small energy losses at discrete wavelengths within the resonant cavity of an organic solution laser could result in quenching of broad band laser emission at those specific wavelengths. These considerations led to investigations in which atoms and mlecules were purposefully introduced into the resonant cavity of an organic solution laser.¹ A search of the literature revealed that investigators at The National Bureau of Standards had previously observed this phenomenon and had reported on the intra-cavity absorption of a pulsed rhodamine 6G laser emission by sodium vapor.² In a follow-up paper Keller and co-workers demonstrated the enhancement of absorption for Eu(NO₃)₃) when placed within the cavity of a rhodamine 6G laser. Concurrently absorption was observed from Ba and Sr in an air-acetylene flame within a dye laser cavity by, Thrash et al.⁴ Hansch and co-workers⁵ duplicated the intra-cavity absorption experiment with iodine vapor and compared the sensitivity of this result with measurements obtained from conventional absorption techniques. At about the same time Latz, Wyles, and Green¹ reported data which dennnstrated that the extent of intra-cavity absorption for nitrogen dioxide was linearly related to its concentration. Investigation into the use of a laminar flow burner with an air-acetylene flame within a dye laser cavity showed part per billion (ppb) detection limits for sodium as well as the detection of barium and mercury. The completion of these intracavity absorption studies in the visible region of the spectrum yielded the results which are reported here as well as quantitative intyacavity absorption data for Eu⁺³. In an independent study Konjevic also reported detection of sodium by intra-cavity absorption from an airnatural gas flame⁶.     

YAG激光同步泵浦染料激光器产生38fs光脉冲

研究表明,不用碰撞脉冲锁模技术,而由一台简单的线型腔染料激光器,就可成功地产生短达38飞秒的光脉冲。这种激光器用六镜折叠腔,其中有Rh6G和DOPCI两个喷流和一个棱镜对色散补偿器,用连续锁模Nd:YAG激光器的倍频输出同步泵浦。染料激光脉冲的平均功率为20mW,脉冲重复频率近100MHz。     

Frequency-narrowed external-cavity broad-area-diode for rubidium laser pumping

Using an external cavity with holographic grating, we demonstrate the spectral narrowing of a high power broad-area-diode with a single emitter. The spectral bandwidth of less than 15 GHz is obtained with output power exceeding 10 W and external cavity efficiency exceeding 60%. Absorption of 98% of the laser radiation by a 25-mm rubidium vapor cell filled with 600-torr ethane at a temperature of 368 K is acquired, which demonstrates the availability of this pump source for efficient rubidium laser pumping.     

Generation of a radially polarized laser beam by use of a conical Brewster prism

To generate a radially polarized laser beam we designed and fabricated a new Brewster optical element that consists of convex and concave conical prisms. The lateral surface of the convex conical prism was coated with a dielectric multilayer (SiO2 and Ta2O5) to enhance polarization selectivity. By combining two prisms we obtained a conical Brewster prism without beam divergence owing to refraction. A radially polarized TEM01* (R-TEM01*) mode laser beam was demonstrated when this prism was used inside a Nd:YAG laser cavity.     

Strong field effect on intracavity atoms in dye lasers: Self frequency-locking

By using a variety of dye laser types and intracavity atoms, the general nature of the narrowing of the dye emission to sharp lines near atomic transition is shown. The rôle of cavity adjustment is stressed. It is suggested that this “self frequency-locking” originates from strong field effects on intracavity atomic vapors.     

基于内腔布儒斯特双轴锥棱镜的掺镱光纤激光器的径向偏振模振荡

实验采用一个内腔布儒斯特双轴锥棱镜,在掺镱多模双包层光纤激光器中实现了径向偏振光振荡,并在长2 m的增益光纤中获得了高达6.2 mW的功率输出.研究揭示了从光纤激光器振荡中获得径向偏振光的新途径.然而,该激光器输出的径向偏振光的光强分布并不很均匀,且偏振消光比较低,需要进一步改进.     

Saturation-dips in the weak calcium intercombination line

Lamb-dips have been observed in the weak calcium intercombination line by monitoring resonance fluorescence in an atomic beam excited by light of a stabilized cw dye laser inside or outside the laser cavity. A highly sensitive detection scheme is described.     

半导体泵浦铷蒸气激光器出光实验

针对中心波长780 nm的商用连续波半导体激光器,使用斩波器将连续激光变为脉冲输出形式,用2400 line/mm的平面全息光栅搭建Littrow外腔将线宽压窄至0.2 nm以下。采用透镜组对线宽压窄后的半导体激光进行光束整形,半导体激光经线宽压窄和光束整形后,经透镜聚焦进长约8 mm的铷蒸气泡进行半导体泵浦碱金属激光实验。首次出光得到17.5 mW的基模线偏振铷激光;在最新的改进实验中,半导体泵浦铷激光输出功率已达到2.8 W。     

钠分子的共振喇曼散射

本文用80mW6238.2(?)的He-Ne激光激发钠蒸气,用一种新颖的棱镜反射光路,从后向首次观察到了56O0～8200(?)钠分子的共振喇曼谱.     

Tunable single-longitudinal-mode SOA-based fiber laser based on the spectral narrowing effect in a dispersion-shifted fiber

A tunable single-longitudinal-mode(SLM) semiconductor optical amplifier(SOA)-based fiber laser based on a dispersion-shifted fiber(DSF) is proposed and successfully demonstrated. SLM operation is obtained due to the spectral narrowing effect resulting from inverse four-wave mixing in a DSF. A tunable optical filter performs wavelength selection function. By inserting a length of DSF in the laser cavity, SLM lasing can possibly be obtained when laser oscillation is stably established after traveling through the DSF many roundtrips. Stable tunable SLM oscillation with a signal-to-noise ratio as high as 65 dB over a wavelength range of about 35 nm is achieved experimentally, and each spectral linewidth is less than 6.5 kHz.     

多谱线He-Ne激光器中棱镜组件的热变形研究

拉曼散射分析通常使用多谱线He-Ne激光器作为光源。通过建立多谱线He-Ne激光器腔内棱镜组件的有限元模型,并进行热变形分析,得到了棱镜组件的热变形位移结果。讨论了在棱镜角度改变时多谱线He-Ne激光器输出谱线的变化情况,通过实验进一步验证了仿真结果的准确性。结果表明:多谱线He-Ne激光器长时间工作会使温度升高,严重影响其腔内棱镜的偏转角度,使得其输出谱线发生一定的漂移。当腔内温度继续升高到一定值时会导致激光器不出光,此时,应当采取散热装置或者温度控制措施。     

碱蒸气激光半导体泵浦源谱宽压窄

 笑脸效应严重制约大功率半导体激光器输出谱宽压窄。为避免笑脸效应,以中心波长780 nm单宽面源大功率半导体激光器为研究对象,利用利特曼外腔结构,优化外腔参数,在激光器自由运转19 W时,获得11.5 W、外腔效率达61%的窄线宽输出。将窄线宽输出激光通过长25 cm, 80 kPa乙烷、110 ℃的铷池,96.7%的泵浦光被吸收,通过与理论模型对比,推断半导体激光器的输出谱宽为15 GHz(0.03 nm)。     

An experimental study and theoretical analysis of the mode characteristics of a narrow line-width,pulsed dye laser oscillator at different pump powers

This paper presents an experimental study and theoretical analysis on the effect of pump power on the divergence, pointing, line-width and wavelength stability of a narrow line-width, high repetition rate dye laser oscillator. The dye laser oscillator, based on the hybrid multiple-prism grazing-incidence grating cavity, was pumped by copper vapor laser (CVL). The dye laser mode characteristics were studied at CVL average pump powers of 2, 4 and 8 W. The single pulse dye laser divergence/pointing stability was studied by far-field intensity distributions. The line-width and wavelength stability were studied using a high resolution wave-meter. The experimental results were theoretically analyzed in terms of dye laser mode structure drift induced by beam pointing instability, beam divergence and thermally induced optical path length fluctuation. A comprehensive theoretical treatment on pointing stability of dye laser beam and its influence in the dye laser wavelength stability is presented. The theoretical and experimental trends were found to be in good agreement.