公开(公告)号：US06466322B1

公开(公告)日：2002-10-15

申请号：US09470903

申请日：1999-12-23

申请人： Barbara A. Paldus ,  Richard N. Zare

发明人： Barbara A. Paldus ,  Richard N. Zare

IPC分类号： G01N2161

CPC分类号： G01N21/39

摘要： An ring-down spectroscopy instrument comprising a ring-down cavity (RDC) and CW light source (CWLS). The CWLS produces light having components with different polarizations. The ring-down cavity is optically isolated from the light source so that light reflected from the cavity is precluded from perturbing the light source. A frequency shifter shifts a mean frequency of the first component of input light with respect to a mean frequency of the second component of input light by a frequency shift &Dgr;&ngr;. A first detector measures a signal beam with the a polarization. A second detector measures a tracking beam having a second polarization. The frequency shift &Dgr;&ngr; is equal to a difference between a resonant frequency of a first cavity mode with the first polarization and a resonant frequency of a second cavity mode having the second polarization. A threshold detector delivers a trigger pulse to the frequency shifter when an intensity of the signal beam reaches a predetermined value. The trigger pulse causes the frequency shifter to temporarily change the frequency shift &Dgr;&ngr;, thereby temporarily decoupling the first component of input light from the ring-down cavity. An embodiment of the invention includes a ring down spectroscopy method. Radiation coupled into a ring-down cavity is swept in frequency by to excite one or more resonant modes of the cavity. When a fundamental mode of the cavity reaches a predetermined threshold value a digitizer produces a ring-down decay curve. An absorption spectrum is determined by extrapolating a decay constant from a logarithm of the decay curve.

摘要翻译： 一种振铃光谱仪，包括一个环形腔（RDC）和CW光源（CWLS）。 CWLS产生具有不同偏振分量的光。 环形腔与光源光学隔离，使得从空腔反射的光不被扰乱光源。 频移器将输入光的第一分量的平均频率相对于输入光的第二分量的平均频率移位频移DELTA＆lt; ngr。 第一检测器测量具有偏振的信号光束。 第二检测器测量具有第二偏振的跟踪光束。 频移DELTA＆ngr; 等于具有第一极化的第一腔模式的谐振频率和具有第二极化的第二腔模式的谐振频率之间的差。 当信号光束的强度达到预定值时，阈值检测器将触发脉冲传送到移频器。 触发脉冲使得移频器暂时改变频移DELTA＆ngr，从而暂时将输入光的第一分量与衰减腔分离。 本发明的实施例包括环形光谱法。 通过激发耦合到环形腔中的一个或多个谐振模式的频率来扫描耦合到环形腔中的辐射。 当空腔的基本模式达到预定阈值时，数字转换器产生衰减衰减曲线。 通过从衰减曲线的对数外推衰减常数来确定吸收光谱。

公开(公告)号：US06452680B1

公开(公告)日：2002-09-17

申请号：US09497309

申请日：2000-02-03

申请人： Barbara A. Paldus ,  Charles Harb ,  Richard N. Zare ,  Gerard Meijer

发明人： Barbara A. Paldus ,  Charles Harb ,  Richard N. Zare ,  Gerard Meijer

IPC分类号： G01N2100

CPC分类号： G01J3/42 ,  G01N21/39

摘要： Method and system for cavity ring down spectroscopic analysis of non-cavity-filling sample. An interface of a sample (gas, liquid, thin film, bulk solid, etc.) is positioned at a Brewster angle relative to a p-wave polarized light beam propagating in an optical cavity so that substantially no light beam energy is lost by reflection at the interface. The light beam cycles one or more times in the cavity for each of a sequence of selected wavelengths, is extracted from the cavity, and is analyzed to determine an absorption spectrum for the sample. The cavity, except for the sample region may be filled with a solid, optionally dielectrically active and optionally having an electrical field applied thereto to vary the solid's refractive index according to the light beam wavelength used.

摘要翻译： 空腔填充样品的腔环下光谱分析方法与系统。 样品（气体，液体，薄膜，体积固体等）的界面相对于在光腔中传播的p波偏振光束位于布鲁斯特角，使得基本上没有光束能量被反射损失 在界面。 对于所选波长序列中的每一个，光束在空腔中循环一次或多次，从空腔中提取，并且被分析以确定样品的吸收光谱。 除了样品区域之外的空腔可以填充固体，任选地介电活性并且任选地具有施加到其上的电场以根据所使用的光束波长改变固体的折射率。

公开(公告)号：US5903358A

公开(公告)日：1999-05-11

申请号：US949241

申请日：1997-10-10

申请人： Richard N. Zare ,  Juergen Martin ,  Barbara A. Paldus

发明人： Richard N. Zare ,  Juergen Martin ,  Barbara A. Paldus

IPC分类号： G01J3/10 ,  G01J3/42 ,  G01N21/39 ,  G01N21/17

CPC分类号： G01J3/10 ,  G01J3/42 ,  G01N21/39

摘要： A cavity ring down spectroscopy (CRDS) system uses a free-running continuous wave (c.w.) diode laser stabilized by frequency-shifted optical feedback in the presence of strong reflections from a high-finesse Fabry-Perot resonator. The frequency-shifted feedback stabilization eliminates the need for tightly controlling the relative positions of the laser and resonator. Non-frequency-shifted feedback is used for linewidth broadening. An acousto-optic modulator placed between the diode laser output and the resonator input frequency-shifts light reflected by the resonator input, causing the laser to cycle in phase with a period equal to the inverse of the frequency-shift. The laser diode linewidth can be stabilized from several MHz for high resolution spectroscopy of species at low pressures, to several hundred MHz for lower resolution spectroscopy of species at atmospheric pressures.

摘要翻译： 空腔环形光谱（CRDS）系统使用在高精度Fabry-Perot谐振器存在强反射的情况下通过频移光学反馈稳定的自由运行连续波（c.w.）二极管激光器。 频移反馈稳定消除了对激光器和谐振器的相对位置的紧密控制的需要。 非频移反馈用于线宽展宽。 放置在二极管激光器输出和谐振器输入之间的声光调制器频移由谐振器输入反射的光，使得激光器以等于频移倒数的周期相位循环。 激光二极管线宽可以从几MHz稳定，用于低压物种的高分辨率光谱，到几百MHz，用于在大气压下物种的较低分辨光谱。