水晶増強光音響分光法(QEPAS)用音響検出モジュール

Designed for Quartz-Enhanced Photoacoustic Spectroscopy (QEPAS)
Acoustic Microresonator Tubes and Matched Preamplifier for Optimal SNR
Custom Quartz Tuning Fork with 0.8 mm Prong Separation
Low Resonance Frequency
High Q Factor

ADM01

Acoustic Detection Module for QEPAS

Zoomed-In View Through Window

Quartz
Tuning
Fork

Microresonator Tubes

See QEPAS Tab for More Details

Please Wait

概要
仕様
QEPAS
Publications
Feedback

Click to Enlarge
モジュール内部図

QEPAS: Quartz-Enhanced Photoacoustic Spectroscopy

特長

カスタム仕様のクォーツチューニングフォーク、マイクロ共振器(µR)チューブ、高利得プリアンプを内蔵
低共振周波数
大気圧でのQファクタ: > 12000(典型値)
小さなサンプルガス体積:7 cm³
200 nm～11 µm用のØ12.7 mm(Ø1/2インチ)フッ化バリウム(BaF₂)ウィンドウ、コーティング無し、ウェッジ付き

音響検出モジュールは水晶増強光音響分光法(QEPAS)システムに簡単に組み込めるように設計された光音響セルです。モジュールADM01には試料ガスが密閉されたチャンバに送り込むためのインレットとアウトレットがあり、そのチャンバ内にはマイクロ共振器チューブとカスタム仕様のクォーツチューニングフォーク(QTF、水晶製の音叉)が納められています。外部のレーザ光源からの光がウェッジ付きウィンドウを通して入射されるとターゲットの分子が励起され、その分子の緩和過程で生成された音響信号はチューブによって増幅されます。その音響信号はカスタム仕様のQTFによって電気信号に変換され、さらに内蔵の高利得プリアンプによって増幅されます。このような構成により、優れたSN比の信号が得られます。この技術についての詳細は「QEPAS」タブをご覧ください。

モジュールADM01は、QEPASシステムに組み込むことができるように設計されています。システム全体を必要とするお客様のために、QEPASセンサQEPAS-CH4をご用意しております。これはメタン検出用に音響モジュールADM01を使用しており、操作も容易です。QEPAS-CH4の詳細や、システム内でADM01がどのように使用されているかについては、メタン検出用QEPASセンサの製品紹介ページをご覧ください。

ガス接続部
各モジュールADM01にはガス接続ポートが2つ付いています。フローセルとしてお使いにならない場合は、2つ目のガスポートは、セルにプレッシャーゲージやその他のデバイスを接続してご使用いただけます。ガスポートには6 mmチューブ用の標準的なステンレススチール製Hylokチューブ継手が付いています。チューブ継手を取り外して、G1/8メス型ストレートネジコネクタをご使用いただくことも可能です。

200 nm～11 µm用のØ12.7 mm(Ø1/2インチ)ウェッジ付きウィンドウは、それ以外の波長で測定したいときには交換することができます。またマイクロ共振器チューブは、N₂ガス以外のマトリックスで測定したいときには交換することができます。詳細については当社までお問い合わせください。

取付けについて
右図でご覧いただけるように、モジュールADM01には直接ブレッドボードに固定するための貫通穴が4つ付いています。モジュールの底部にはスロット付き取付けプレートPY005A1/M上の5軸ステージPY005/Mに取り付けるためのM4タップ穴が付いています。この組み合わせで使用するときは、まず5軸ステージをスロット付きプレートに取り付け後、モジュールADM01をステージ上に取り付けてください。そして最後にPY005A1/Mのスロットを使用してアセンブリ全体をブレッドボードに取り付けてください。モジュールには、回転止め用のØ2.1 mm穴がいくつか付いています。5軸ステージのM3タップ穴にDIN915ネジを1個取り付け、そのDIN915の頭を4つあるØ2.1 mm穴の1つに入るようにするとモジュールの回転位置が固定されます。

アライメント
レーザ光源とモジュールADM01とのアライメントは、2枚のミラーでビームをステアリングするか、あるいはモジュールを5軸ステージPY005/Mのような多軸ステージに取り付けることで調整できます。光熱効果の影響を排除するため、レーザービームはチューブ面に当たらないようにしなくてはなりません。そのため、ビーム径はチューブ内径の1.6 mmより小さくする必要があります。パワーセンサを用いてモジュールの前後でパワー損失が無いかどうかを測定し、ビームがチューブ面に当たっていないことを確認することができます。信号強度を最適化するために、QTFの位置でレーザ光が集光するようにレンズを置くこともできます。

なお、こちらの製品の廃棄については、当社までご相談ください。

Electrical Connections
Color	Purpose	Comment
Red	+12 V	Recommended Voltage, up to 24 V Maximum
Black	GND	-
Blue	-12 V	Recommended Voltage, up to 24 V Maximum
White	MODULATION IN	Electrical Modulation (sine) IN for QTF Characterization
Green	SIGNAL OUT	Amplified QTF Signal OUT Linear up to 1.8 V, 50 Ω Termination

ADM01 Specifications
Resonant Frequency f₀ ^a	12455 Hz (Typ.)
Q Factor^a	> 12000 (Typ.)
Volume of Sample Chamber	7 cm³
Microresonator Tubes (2)	Inner Diameter: 1.6 mm Length, Each: 12.4 mm
Wedged Windows^b(2)	WW00530 Uncoated BaF₂, 200 nm - 11 µm
Gas Connectors	G1/8 Straight for 6 mm Tubing
Recommended Gas Flow	< 200 sccm
Maximum Gas Pressure	1.5 bar

大気圧
ウェッジ付きウィンドウは別の励起波長に適したウィンドウに交換することも可能です。詳細は当社までお問い合わせください。

Click to Enlarge
QEPASの概要図

光音響分光法は光音響効果に基づく技術で、トレースガスの濃度を精度良く検出することができ、様々な用途に用いることができます。レーザ吸収分光法と同様に気密チャンバ内にレーザ光を導入し、ターゲットのガス分子を励起します。しかし光検出器で吸収線を検出するのではなく、励起された分子の緩和過程で生成された圧力波をトランスデューサで検出します。

水晶増強光音響分光法(QEPAS)の場合は、このトランデューサとして鋭い共振ピークを持つクォーツチューニングフォーク(QTF)が用いられます。音響に対する共振のQ値が高いため、従来の手法における音響共振についての制限を越え、小さな体積での微弱な励起も検出することができます。レーザ光を正弦波で変調したとき、生成される圧力(音響)波の周波数は光の変調周波数の2倍になるため、レーザ光の変調周波数はQTFの共振周波数の半分に設定しなければなりません。QTFから得られる振幅はサンプル内のトレースガスの濃度に正比例します。

またQTFは音響的には四重極子であることから耐環境ノイズの点でも優れています。これは1次振動モードで圧電的に活性になるためには、QTFのプロングが互いに離れる方向に動かなければならないためです。外部からの音の波長はプロング間の距離よりも長く、従ってそのような音は2つのプロングを同じ方向に動かすことになり、結果として圧電的な応答は発生しません。

QEPASの原理について詳細は「Publications」タブをご参照ください。

音響検出モジュールADM01
モジュールADM01はOn-Axis型のQEPASとして設計されており、右の図のようにQTFの両側に光を通過させる音響マイクロ共振器のチューブが配置されています。各チューブの長さはおよそλ/2で、QTFとの間に小さな隙間があります。ここで、λはQTFの共振周波数の音波の大気中における波長です。音響マイクロ共振器は生成された音波とQTFとの相互作用長を増大させるため、QTFは近接した場で生成された光音響波に対する高い感度を得ることができます。

Select Publications on Quartz-Enhanced Photoacoustic Spectroscopy

The following publications provide further information on the principles and applications of QEPAS. For more information, we suggest visiting the website of our strategic partners at PolySense, a joint industry-university research lab between Thorlabs and the Technical University of Bari focused on the research and development of innovative optical gas sensing systems.

2023

R. De Palo, A. Elefante, G. Biagi, F. Paciolla, R. Weih, V. Villada, A. Zifarelli, M. Giglio, A. Sampaolo, V. Spagnolo, and P. Patimisco, "Quartz-Enhanced Photoacoustic Sensors for Detection of Eight Air Pollutants," Adv. Photonics Res. 4, 2200353 (2023)

2022

H. Lin, Y. Liu, L. Lin, W. Zhu, X. Zhou, Y. Zhong, M. Giglio, A. Sampaolo, P. Patimisco, F.K. Tittel, J. Yu, V. Spagnolo, and H. Zheng, "Application of standard and custom quartz tuning forks for quartz-enhanced photoacoustic spectroscopy gas sensing," App. Spec. Rev. 57, (2022)

A. Sampaolo, P. Patimisco, M. Giglio, A. Zifarelli, H. Wu, L. Dong, and V. Spagnolo, "Quartz-enhanced photoacoustic spectroscopy for multi-gas detection: A review," Anal. Chim. Acta 1202, 338894 (2021)

2021

P. Patimisco and V. Spagnolo, "Quartz-Enhanced Photoacoustic Spectroscopy for Trace Gas Sensing," Encycl. Anal. Chem. 1-17, (2021)

2020

A. Sampaolo, G. Menduni, P. Patimisco, M. Giglio, V.M.N. Passaro, L. Dong, H. Wu, F.K. Tittel, and V. Spagnolo, "Quartz-Enhanced Photoacoustic Spectroscopy for Hydrocarbon Trace Gas Detection and Petroleum Exploration," Fuel 227, 118118 (2020)

2018

P. Patimisco, A. Sampaolo, L. Dong, F.K. Tittel, and V. Spagnolo, "Recent advances in quartz enhanced photoacoustic sensing," App. Phys. Rev. 5, 011106 (2018)

2016

P. Patimisco, A. Sampaolo, H. Zheng, L. Dong, F.K. Tittel, and V. Spagnolo, "Quartz-enhanced photoacoustic spectrophones exploiting custom tuning forks: a review," Adv. Phys. X 2, 169-187 (2016)

2014

P. Patimisco, G. Scamarcio, F.K. Tittel and V. Spagnolo, "Quartz-Enhanced Photoacoustic Spectroscopy: A Review," Sensors 14, 6165-6206 (2014)

Posted Comments:

user (posted 2023-12-20 16:44:40.343)

尊敬的先生/女士，我正在与您联系以获取有关 adm 模块的更多信息，并获得有关我们的光声光谱实验设置的建议。你能通过电子邮件与我联系吗？

nreusch (posted 2023-12-21 02:54:33.0)

Thank you for contacting Thorlabs. An applications engineer from our team in China (techsupport-cn@thorlabs.com) has reached out to you directly regarding this. 感谢联系Thorlabs！来自中国的技术支持同事（techsupport-cn@thorlabs.com）将直接与您联系沟通。

Eda Güney (posted 2023-11-10 14:18:08.433)

Dear Sir/Madam, I am contacting you to get more information about adm modules and get suggestions about our photoacoustic spectroscopy experimental setup. Could you please contact me via e-mail? Best

soswald (posted 2023-11-10 07:50:14.0)

Dear Eda, thank you for your feedback. I have reached out to you directly to discuss your setup in detail.

user (posted 2023-10-30 20:50:44.05)

Hii, 1)How to characterize the QTF? 2)Can we change the QTF with a customized QTF version? 3)Dimensions of the QTF?

nreusch (posted 2023-10-30 11:50:01.0)

Thank you for your feedback. 1) It is important to characterize the QTF and to determine the resonance frequency under the measurement conditions in your project. For doing so, the white MODULATION IN wire should be employed. A sinus signal will be applied between GND and this wire and the frequency should be swept. The resonance frequency is then detected as a peak in the response of the SIGNAL OUT/green wire. A typical voltage would be 200 mV pp. 2) The combination of QTF and micro resonator tubes was optimized during development. Therefore, we do not recommend exchanging the QTF. If your application requires a different QTF design, we will need to discuss whether our mechanics and electronics would still be a good match for project. 3) We can provide the dimensions of the QTF. I will reach out to you to discuss all of the above in more detail.

Aritra Pal (posted 2023-06-01 20:11:01.143)

Can you please post a picture of the entire QEPAS setup where we can see where to place the ADM01, above what should we place. I am actually unable to fix the ADM01 on the MTA translation stage...actually I am not even sure if I should place it there only...

soswald (posted 2023-06-01 09:23:53.0)

Dear Aritra, thank you for your feedback. I have reached out to you directly to discuss your setup in detail.

user (posted 2023-04-25 21:40:57.607)

Hello, I was wondering if it is possible to use the ADM module with the harmonics of the resonance frequency, and if it is possible, how this affects the signal. Is this something that has been tested before? Thank you for your assistance.

soswald (posted 2023-04-26 05:36:05.0)

Thank you for your feedback. In principle the QEPAS technique can be used for dual-gas detection using the harmonics of the resonance frequency of the quartz tuning fork as separate detection channels. However, the signal intensity of the higher harmonics is much lower than the fundamental, so this requires a quartz tuning fork specifically designed and optimized for this purpose, which the standard quartz tuning fork incorporated into the ADM01 is not.

user (posted 2023-04-11 16:56:59.14)

I'm curious about what material is used on the electrodes deposited on the quartz tuning fork, to possibly use this unit to detect corrosive gases at low concentrations. What are the electrodes made of?

soswald (posted 2023-04-12 04:47:09.0)

Thank you for your feedback. The electrodes are made of gold. I have reached out to you directly to discuss your application in detail.

user (posted 2022-06-07 17:37:05.363)

Is there a diagram or explanation available describing how the input modulation works? What exactly is the modulation affecting, and how is it transduced by the QCTF and amplified by the TIA?

mdiekmann (posted 2022-06-23 02:41:24.0)

The input modulation is a sine with user set amplitude (typ. 100-300mV) and frequency. The amplitude is scaled down on the preamplifier. This excites the QTF and depending on how well the frequency corresponds to the resonance frequency, the QTF gives a signal which is is amplified by the TIA in the same way it would if it was excited by a laser. Please do not hesitate to reach out to your local tech support team in case you have further questions.

李玉林 (posted 2021-09-14 15:05:34.77)

请问ADM01成套装置只需要接入准直出来的可调激光（例如1653nm）就可以得到测量结果吗？不需要其他配件了吧？

dpossin (posted 2021-09-21 09:09:56.0)

Dear Customer, Thank you for your feedback. Well thats right. The measurement can be done right away as long as you have an tunable collimated laser.

KwangHoon Ko (posted 2021-05-20 20:13:57.183)

I have an ADM01 QEPAS cell and I am connecting the wires of QEPAS now. But there's no maximum voltage amplitude and frequency for modulation input (white wire) in manual. So, please let me know the operation voltage (amplitude) for modulation input. And about the frequency, I think the frequency is 12455 Hz. Please confirm this. Thanks.

dpossin (posted 2021-05-21 05:31:23.0)

Dear KwangHoon Ko, Thank you for your inquiry. We use 300mV in order to characterize the QTF. In front of the TIA, there is an voltage divider which scales the input voltage down to factor 1/285. In order to find out the maximum modulation input at MOD IN you can start with 300mV and while continously measure the output voltage slowly increase the modulation voltage until 1.8V is reached at the amplified output. At this point and above the TIA leaves the linear regime and stops working above 2.2V. I am reaching out to you in order to discuss this further.

J.-F. Lampin (posted 2021-03-09 09:28:23.167)

Dear Thorlabs, Your QUEPAS is very interesting but I can not modulate my MIR source. A solution would be to chop the beam but your chopper as a maximum frequency of 10 kHz which is lower than the resonant frequency of the QEPAS (12.4 kHz). Do you see a solution ? Thanks.

dpossin (posted 2021-03-12 07:33:56.0)

Dear Jean Francois, Thank you for your feedback. It is not absolutely neccessary to modulate the laser incident to the ADM01 module in the time domain. Another technique is to modulate the laser in the spectral regime with half the resonant frequency of the quarz tuning fork. This is our preferred technique and I guess most of our customers use the QUEPAS module this way. I am reaching out to you to discuss this further.

Michał Pawlak (posted 2020-08-06 04:49:36.65)

Is it possible to do the sample holder for solid sample? circles around 1 cm in diamieter and 1mm thinck?

dpossin (posted 2020-08-11 05:47:28.0)

Dear Michal, Thank you for your feedback. As the ADM01 is an QUEPAS system (please see a brief introduction to the principle here: LINK) which only works for gases the placement of solid samples does not make sense. I reached out to your in order to further discuss your application.

Ryan Sun (posted 2020-05-27 04:25:02.667)

Dear Thorlabs, I am trying to lower the pressure inside the ADM01 to 1Torr. I want to know if the ADM01's window can withstand a relative pressure of almost 1atm and if it can be repaired if it breaks. I completed the test from 1.5bar to 0.5bar pressure, but the experiment was stopped because I was not sure whether the ADM01 could work normally at a pressure of 0.5bar or less. Please explain the exact limit of the window installed in ADM01. Thank you :)

wskopalik (posted 2020-06-04 06:54:09.0)

This is a response from Wolfgang at Thorlabs. Thank you for your inquiry! The windows in the ADM01 can withstand a pressure of 1 Torr on the inside. We have tested the ADM01 successfully with low pressures in this range. There would however need to be continuous gas flow and pumping at such low pressures to keep the pressure low. In the case of static measurements at low pressures, the pressure would rise quickly, i.e. you would draw air from the outside. In case of a damage, the windows can easily be exchanged. The windows WW00530 are used in the ADM01 which are available in our catalog. I will contact you directly to provide further assistance.

yazhou wang (posted 2020-04-23 14:01:50.773)

Hello, It mentioned that: 'When the laser source is modulated with a sine wave, the induced pressure (sound) wave will have double the frequency as that of the light modulation; therefore, the laser source modulation must be at half of the resonance frequency of the quartz tuning fork (QTF).' I feel confused that why the induced pressure (sound) wave will have double the frequency as that of the light modulation. Cloud you please give some comments on this? Thanks!

dpossin (posted 2020-05-04 04:22:19.0)

Dear Customer, Thank you for your feedback. Well, for photoacoustic purposes the frequency of the incident laser light is modulated. Therefore the absorption line of the gas inside the QUEPAS cell is hit twice within one full modulation wave. One time in the first half wave when the laser wavelenght rises and a second time in the second half wave when the laser wavelenght drops again. The vibronic movement of the gas leads to sound waves which have double the modulation frequency of those of the incident laser light. To make sure, that the resonance frequency of the quartz tuning fork (QTF) is met, the modulation of the incident laser must be half the resonance frequency of the QTF. Because the bandwith of the QTF is quite narrow it is crucial that the resonance freqency is hit. I am reaching out to you for further discussion.

Mincheol Jeon (posted 2020-02-02 19:48:57.607)

Hello Thorlabs, in sepcs, its maximum gas pressure is 1.5bar. But how about in vacuum? Is it possible to measure gas with adm01 even in vacuum? Thank you!

dpossin (posted 2020-02-19 08:16:39.0)

Dear customer, Thank you for your feedback. There are many things to care of when you like to evacuate the ADM01 chamber. As an example I will enlarge on two different topics: Leakage: How good the vacuum can be depends very much on the leakage rate and the power of the pump. Leakage rate is given by the seals of the ADM01 cell itself and also on the fact if and how much the inner components are outgasing. As we did not tested the ADM01 for that purpose we can not say if vacuum can be applied there. However the Entrance and output windows withstand the ambient pressure. Limit of detection (LOD): The limit of detection also depends on the pressure as for lower gas pressure or even vacuum, there won´t be ambient gas any more which transmits the vibrational movements onto the tuning fork. As an result, most probably the LOD will decrease.

Ryan Sun (posted 2020-01-13 03:50:37.59)

Dear Thorlabs, Could you explain to me what is the current's range(ampere) required by the power supply of ADM01?

nreusch (posted 2020-01-14 02:04:48.0)

This is a response from Nicola at Thorlabs. Thank you for contacting us. The current consumption is about 20-30 mA.

Mincheol Jeon (posted 2019-12-06 03:21:37.25)

Dear Thorlabs, could you please inform the drawing or size of the QTF?(ex. width, length of each tine and length between two tines...) Thank you!

nreusch (posted 2019-12-09 02:30:37.0)

This is a response from Nicola at Thorlabs. Thank you for your feedback. You can download the AutoCAD file by clicking on the red document icon next to the item number and then choosing the Auto CAD PDF document or any other file format that you are interested in. Please contact your local Tech Support team if any information is missing.

Mincheol Jeon (posted 2019-11-11 04:56:58.69)

I want to know what kind of the electrical modulation(sine) IN for QTF characterization.(voltage modulation? or current modulation..) And I want to know how much modulation input I have to put in. Best regards, Mincheol.

dpossin (posted 2019-11-12 03:21:26.0)

Hello Mincheol, Thank you for your feedback. To characterize the QTF an sine signal between 3 and 50 mV (peak to peak) shall be applied. The actual voltage level depends on the pressure inside the measuring cell. To find the resonance frequency of the QTF one should start with a frequency slightly below 12455 Hz and slowly increase the frequency until resonant vibration is found. Please note that the applied voltage into the MODULATION IN is reduced by an factor of 256 via an voltage divider before it reaches the QTF.

Mincheol Jeon (posted 2019-11-11 04:53:01.51)

I want to know what kind of the electrical modulation(sine) IN for QTF characterization.(voltage modulation? or current modulation..) Best regards, Mincheol.

Jean-Michel Melkonian (posted 2019-09-20 08:41:50.633)

Dear Thorlabs, could you please update the specs of ADM01 to confirm whether it can be pumped down to near vacuum, because in relative pressure this results in -1 bar. Thank you.

MKiess (posted 2019-10-14 06:08:23.0)

This is a response from Michael at Thorlabs. Thank you for the Feedback. We stated 1.5bar maximum pressure since that was up to now the maximum we tested with QEPAS measurements and are confident that it works. In terms of vacuum the lower limit depends on two factors: the tightness of the ADM01 and the pump that is used to evacuate. The strongest pump we have in our labortory brought us to the lower limit. The pressure sensor we have can measured 1Torr. Therefore, it would be worth considering changing the pressure specifications as follows: 1mbar to 1.5 bar (absolute pressure), i.e. from 1 Torr to 1125 Torr.

Ryan Sun (posted 2019-09-09 16:37:17.883)

I wonder if the Maximum Gas Pressure in the specifications is absolute or relative. And what is the available temperature range of the module? Please explain these things, Best Regards. Ryan

dpossin (posted 2019-09-10 09:10:56.0)

Hello Ryan, Thank you for your feedback. In general, the epoxy adhesive limits the mechanical use of the ADM module. The specified temperature range of this adhesive is from -40°C up to +90°C. Further the noise of the integrated pre amplifier shows higher noise with respect to increasing temperature. The temperature range for this part is -40°C up to 125°C. The specified pressure is given in absolute value.