CN109187345B - Trigger signal generator for ultrafast time domain spectroscopy system - Google Patents
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- CN109187345B CN109187345B CN201811045844.2A CN201811045844A CN109187345B CN 109187345 B CN109187345 B CN 109187345B CN 201811045844 A CN201811045844 A CN 201811045844A CN 109187345 B CN109187345 B CN 109187345B
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- 230000005684 electric field Effects 0.000 description 9
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- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3581—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using far infrared light; using Terahertz radiation
- G01N21/3586—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using far infrared light; using Terahertz radiation by Terahertz time domain spectroscopy [THz-TDS]
Abstract
The invention discloses a trigger signal generator for an ultrafast time domain spectroscopy system, which utilizes the laser spectrum coherence principle to generate an optical trigger signal when two laser pulses of pump laser and detection laser of the ultrafast time domain spectroscopy system are superposed, and then a high-speed photodiode converts the optical trigger signal into an electrical trigger signal; then the signals are processed by an operational amplifier, a high-pass filter and a Schmitt trigger in sequence and then are sent to an ultrafast time domain spectrum system to be used as a trigger signal of a signal acquisition system, so that a very stable THz time domain spectrum can be obtained; the high-speed photodiode, the operational amplifier, the high-pass filter and the Schmitt trigger are all packaged on the same PCB, so that the function of converting two rows of periodically superposed optical pulses into square signals with the same period and sharp rising edges is realized. The device has the advantages of high integration level, simple structure, high bandwidth, sharp rising edge, easy adjustment and stable performance.
Description
Technical Field
The invention belongs to the technical field of terahertz, and particularly relates to a trigger signal generator for an ultrafast time domain spectroscopy system.
Background
The existing ultrafast time domain spectrum system realizes the high-speed acquisition of time domain spectrum by using an asynchronous sampling principle. The terahertz ultrafast time-domain spectroscopy system based on asynchronous sampling uses two femtosecond lasers with slightly different repetition frequencies, wherein one path of the femtosecond lasers has the repetition frequency of f and serves as a detection pulse, the other path of the femtosecond lasers has the repetition frequency of f + delta f and serves as a pumping pulse, and the repetition frequency of the pumping pulse is controlled by high-bandwidth feedback electronic equipment. The repetition frequency of two femtosecond pulses has a difference of deltaf, so as to increase the time delay of the pump pulse and the probe pulse, and the scanning period T can be given by deltaf, namely T is 1/deltaf. The sampling principle of the ultrafast terahertz time-domain spectroscopy system is shown in fig. 1, where Δ f is 10kHz and T is 100 μ s.
Since the repetition frequencies of the pump pulses and the probe pulses are not the same, they are not synchronized but coincide at regular intervals. When the pumping pulse and the detecting pulse coincide once, the end of the scanning period is marked, and the next scanning period starts. The control system should generate a high level pulse signal, i.e. a trigger signal (such as the trigger signal in fig. 1). The period T of the trigger signal is 1/Δ f. The time T is also the sampling period of the signal acquisition system, the signal acquisition system starts to acquire data after receiving a trigger signal, finishes the acquisition after receiving the next trigger signal, stores the data and starts to acquire the data in the next period. The trigger signal is critical to the acquisition of the signal.
There are two ways of generating the trigger signal: based on optical generation methods, based on electrical generation methods.
There are two ways based on the optical generation method: 1. in the two-photon detector method, the two-photon absorption effect can be generated only under two paths of strong laser, so that the two paths of strong laser can cause great damage to the photodiode, and the detector is easy to damage. 2. The method of frequency doubling crystal is based on the frequency doubling principle of frequency doubling crystal, but has low conversion efficiency, poor anti-interference performance, difficult packaging and inconvenient use.
Based on an electricity generation method, the method is that two pulse light signals are converted into two rows of separated electric pulse signals, and then the two rows of separated electric signals are converted into trigger signals by a trigger circuit. The disadvantages are as follows: in high frequency circuits, the stability is poor and has now been abandoned.
Disclosure of Invention
In view of the above, an object of the present invention is to provide a trigger signal generator for an ultrafast time domain spectroscopy system, which can generate a trigger signal with a sharp rising edge, easy adjustment, simple structure, high bandwidth and stable performance by using the principle of laser spectrum coherence.
A trigger signal generator for an ultrafast time domain spectroscopy system comprises a photodiode, a high-pass filter, a trans-impedance amplifier, an operational amplifier and a Schmitt trigger;
the photodiode receives coherent pulse signals of pump laser and detection laser of the ultrafast time domain spectroscopy system and converts the coherent pulse signals into electric signals;
the high-pass filter is used for filtering direct current signals in the electric signals output by the photodiode;
the trans-impedance amplifier is used for converting a current signal output by the photodiode into a voltage signal and removing high-frequency noise in the signal;
the operational amplifier is used for further amplifying the voltage signal output by the trans-impedance amplifier;
the Schmitt trigger is connected behind the operational amplifier and used for changing the signal into a square wave signal with sharp rising edges, so that a trigger signal is obtained.
Preferably, the bandwidth of the photodiode is more than 1 GHz.
Preferably, the photodiode is an EOT photodiode with model number ET-400.
Preferably, the model of the core device of the trans-impedance amplifier and the operational amplifier is OPA 657.
Preferably, the photodiode, the operational amplifier, the high-pass filter and the schmitt trigger are all packaged on the same PCB.
The invention has the following beneficial effects:
the invention relates to a trigger signal generator for an ultrafast time domain spectroscopy system, which utilizes the laser spectrum coherence principle to generate an optical trigger signal when two laser pulses of pump laser and detection laser of the ultrafast time domain spectroscopy system are superposed, and then a high-speed photodiode converts the optical trigger signal into an electrical trigger signal; then the signals are processed by an operational amplifier, a high-pass filter and a Schmitt trigger in sequence and then are sent to an ultrafast time domain spectrum system to be used as a trigger signal of a signal acquisition system, so that a very stable THz time domain spectrum can be obtained; the high-speed photodiode, the operational amplifier, the high-pass filter and the Schmitt trigger are all packaged on the same PCB, so that the function of converting two rows of periodically superposed optical pulses into square signals with the same period and sharp rising edges is realized. The device has the advantages of high integration level, simple structure, high bandwidth, sharp rising edge, easy adjustment and stable performance.
Drawings
FIG. 1 is a schematic diagram of a sampling principle of an existing asynchronous sampling time-domain spectroscopy system;
FIG. 2 is a functional block diagram of a trigger signal generator of the present invention;
FIG. 3 illustrates the conversion of an optical trigger signal to an electrical trigger signal by a high speed diode according to the present invention;
FIG. 4 shows the trigger signal at 1430KHz,;
FIG. 5 is an output signal of an operational amplifier (Amp);
FIG. 6 is a time domain amplified electrical pulse;
FIG. 7 shows Schmitt trigger signals
FIG. 8 is a schematic diagram of a trigger generator according to the present invention;
FIG. 9 is a diagram showing the output signals at the output SMA-J of the Schmitt trigger in the trigger signal generator according to the present invention;
FIG. 10 is a signal time domain diagram of the ultrafast time domain spectroscopy system of FIG. 8 acquired using the trigger signal generated by the trigger signal generator of the present invention.
Detailed Description
The invention is described in detail below by way of example with reference to the accompanying drawings.
As shown in fig. 2, in the trigger signal generator for an ultrafast time-domain spectroscopy system according to the present invention, the light receiving device is mainly a high-speed photodiode PD, and the resistance of the high-speed photodiode decreases when receiving a light pulse, and when the light intensity is less than the maximum light intensity, the resistance decreases as the light intensity increases. Its bandwidth is more than 5 times the repetition frequency of the laser. The bandwidth requirement of the high-speed photodiode is more than 1GHz, and the embodiment of the invention adopts the photodiode with the model number ET-400 of EOT company. The high speed photodiode is powered by the DC BISA + supply terminal, in this case 5V. When the optical trigger signal is used, the two laser beams are combined to generate interference action to form an optical trigger signal. This high speed photodiode will complete the conversion of the optical trigger signal to the electrical trigger signal.
The principle of generating the trigger signal is explained in detail below:
two femtosecond pulses are simplified into two monochromatic Gaussian femtosecond pulses, wherein one femtosecond pulse is a pumping pulse, and the other femtosecond pulse is a probe pulse. The electric fields of the two laser beams can be respectively expressed as follows
Wherein Em (T), Es (T) are respectively a pumping pulse electric field and a detection pulse electric field, the peak values of two Gaussian femtosecond pulse electric fields of Em and Es, T0 is the pulse width of the pulse, omega is the angular frequency of the Gaussian femtosecond pulse electric field, and tau is the delay time of the detection pulse relative to the pumping pulse. The initial phase of two Gaussian femtosecond pulse electric fields is defaulted at the position
And the electric field polarization direction is the same.
When two Gaussian femtosecond pulses meet, coherent superposition is generated, and the total electric field after superposition can be expressed as the following form:
the total electric field energy after the coherent superposition of the two Gaussian femtosecond pulses can be expressed as follows:
therefore, the light intensity obtained after the coherent superposition of the two Gaussian femtosecond pulses can be expressed as follows:
redefining each term of the above equation:
wherein A (tau) is the light intensity when the two pulses do not generate coherent action, and B (tau) is the light intensity of the coherent term of the two pulses. A (τ) may be further rewritten as a (τ) ═ C (τ) + D (τ),
in order to pump the energy of the pulse,
to detect energy.
Then equations (1-5) can be rewritten as:
I(τ)＝A(τ)+B(τ) (1-8)
it is calculated from expressions (1-6) and (1-7), and when τ is 0, a (0) is B (0). Namely, the light intensity after the coherent superposition of the two Gaussian femtosecond pulses is twice as much as the light intensity after the incoherent superposition. The response time (in the order of hundreds of ps) of the photodiode used in the detection of the light intensity is much longer than the pulse width. The strongest energy is detected when the relative time delay of the two pulses is 0, which is the spectral complete coherence energy I (0) in the wave packet, i.e. when the photodiode responds most strongly to the pulse. As the relative time delay of the two pulses increases, the photodiode response pulse becomes weaker. When the relative time delay reaches hundreds of femtoseconds to tens of picoseconds, the two pulses have no coherent action, namely B (tau) is 0, but the two pulses can not be distinguished by the detector at the moment, so that incoherent total energy of the two pulses, namely A (tau), is detected, but the response of the detector is smaller along with the increase of the relative time delay. When the relative time delay of the two pulses increases to several hundred picoseconds, the detector can detect the energies C (τ) and D (τ) of the two pulses respectively. The detector response intensity is at a minimum. With this method, the period of two pulses with a periodic time delay can be detected.
As shown in fig. 3, the trigger signal is an ac signal to which a dc signal is added, so a high-pass filter (HPF) is added behind the high-speed photodiode to remove the dc signal. The high-speed photodiode has extremely high bandwidth for photoelectric conversion, and can generate stable trigger signals up to 1430kHz, as shown in FIG. 4.
The high-pass filter is connected with a trans-impedance amplifier (TIA) and an operational amplifier (Amp) in series, and the trigger signal generated by the high-speed diode is amplified. A transimpedance amplifier (TIA) is a front-end amplifier of a high-speed photodiode for converting the output current (I) of the high-speed photodiode to a Voltage (VOUT). The transimpedance amplifier uses a feedback Resistor (RF) across the operational amplifier, according to ohm's law: the Voltage (VOUT) is a current (I) × the feedback Resistance (RF) converting the current (I) into the Voltage (VOUT). And the trans-impedance amplifier (TIA) has a certain bandwidth and can remove high-frequency noise. The operational amplifier (Amp) is a high-speed amplifier with a very high amplification factor, and further amplifies the low-noise voltage signal output by the transimpedance amplifier (TIA). The output voltage signal can meet the requirements of the following Schmitt trigger. The core component of these two amplifiers is OPA657 and their bandwidths are set to 550 MHz. The output signal of the operational amplifier (Amp) is shown in fig. 5.
The output signal of the operational amplifier (Amp) is actually a periodic electrical pulse signal, and since the electrical pulse signal is generated by sequentially irradiating a plurality of optical pulses, the real time domain signal is amplified to be in the form of an electronic pulse envelope, as shown in fig. 6.
The data acquisition system recognizes the rising edge of the trigger signal, but the signal has multiple rising edges, and the trigger directly used for data acquisition causes trigger disorder. The signal of the output of the operational amplifier (Amp) is input to a Schmitt trigger, Schmitt trigger. The schmitt trigger threshold voltage is adjusted to turn the signal into a sharp rising edge square wave signal, as shown in fig. 7.
The Schmitt trigger signal is output through a signal output end SMA-J, and the signal output end of the Schmitt trigger is the output end of the trigger signal generator.
The trigger signal generator can be put into an ultrafast time domain spectroscopy system for use, and the structural schematic diagram of the ultrafast time domain spectroscopy system is shown in FIG. 8. Two femtosecond lasers are used in the system, one is used for generating THz signals by pumping laser, and the other is used for detecting the THz signals. The two femtosecond laser devices have different repetition frequencies, and the difference of the repetition frequencies is delta f, so that the laser pulses of the two laser devices can be periodically overlapped, and the period is 1/delta f. The coincidence of the light pulses is realized, and the trigger signal detector of the invention is used for detecting the coincidence moment of the two laser light pulses. That is, when two light pulses coincide, the trigger signal detector should output a high level signal, and when two light pulses do not coincide, the low level state is maintained. The rising edge of the output signal of the trigger signal generator occurs with a frequency Δ f. In the ultrafast time domain spectroscopy system, the pumping light pulse and the detection light pulse irradiate on a high-speed photodiode of the trigger signal detector after being combined. The average intensity of the two light beams irradiated on the high-speed photodiode is adjusted to be equal to 1/4 of the saturation intensity of the high-speed photodiode. At this time, the output signal of the trigger signal generator is a periodic square wave signal, and the period of the periodic square wave signal is the same as the time domain period of the two rows of envelopes, namely, the reciprocal of the difference between the repetition frequencies of the two rows of pulses. This signal is the trigger signal for the data acquisition system. The output signal of the trigger signal generator is shown in fig. 9.
The trigger signal is input to the data acquisition system as a trigger signal for the data acquisition system. Tells the data acquisition system the end of this cycle and the beginning of the next cycle and saves the data for this cycle. The stable trigger signal can ensure that the position of the THz signal in the whole period is unchanged when the signal is obtained by an integral average method in multiple measurements, and has a vital effect on the accuracy of the final THz signal.
The THz signal is acquired by the trigger signal generated by the trigger signal detector, and the signal time domain diagram is shown in FIG. 10. It can be seen from fig. 10 that the THz time domain spectrum acquired by the trigger signal generated by the trigger signal generator as a trigger source is very stable.
In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (5)
1. A trigger signal generator for an ultrafast time domain spectroscopy system is characterized by comprising a photodiode, a high-pass filter, a trans-impedance amplifier, an operational amplifier and a Schmitt trigger;
the photodiode receives coherent pulse signals of pump laser and detection laser of the ultrafast time domain spectroscopy system and converts the coherent pulse signals into electric signals;
the high-pass filter is used for filtering direct current signals in the electric signals output by the photodiode;
the trans-impedance amplifier is used for converting a current signal output by the photodiode into a voltage signal and removing high-frequency noise in the signal;
the operational amplifier is used for further amplifying the voltage signal output by the trans-impedance amplifier;
the Schmitt trigger is connected behind the operational amplifier and used for changing the signal into a square wave signal with sharp rising edges, so that a trigger signal is obtained.
2. The trigger signal generator for an ultrafast time-domain spectroscopy system of claim 1, wherein the bandwidth of the photodiode is above 1 GHz.
3. The trigger signal generator for an ultrafast time domain spectroscopy system of claim 2, wherein the photodiode is an EOT model ET-400 photodiode.
4. The trigger signal generator for an ultrafast time-domain spectroscopy system of claim 1, wherein the transimpedance amplifier and operational amplifier has a core device model of OPA 657.
5. The trigger signal generator for an ultrafast time-domain spectroscopy system of claim 1, wherein the photodiode, the operational amplifier, the high pass filter, and the schmitt trigger are all packaged on a same PCB.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4475396A (en) * | 1982-07-16 | 1984-10-09 | General Electric Company | Method of determining ultrasonic attenuation of tissue using reflective tomographic reconstruction |
| CN105891144A (en) * | 2016-03-31 | 2016-08-24 | 上海理工大学 | Terahertz scanning system and method |
| CN106442378A (en) * | 2016-09-26 | 2017-02-22 | 上海理工大学 | Device for improving test accuracy of spectrum absorbance on basis of terahertz optical combs |
| CN206226389U (en) * | 2016-11-21 | 2017-06-06 | 国家电网公司 | The frequency selection circuit that active RLC narrow-band pass filters are combined with Schmidt trigger |
-
2018
- 2018-09-07 CN CN201811045844.2A patent/CN109187345B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4475396A (en) * | 1982-07-16 | 1984-10-09 | General Electric Company | Method of determining ultrasonic attenuation of tissue using reflective tomographic reconstruction |
| CN105891144A (en) * | 2016-03-31 | 2016-08-24 | 上海理工大学 | Terahertz scanning system and method |
| CN106442378A (en) * | 2016-09-26 | 2017-02-22 | 上海理工大学 | Device for improving test accuracy of spectrum absorbance on basis of terahertz optical combs |
| CN206226389U (en) * | 2016-11-21 | 2017-06-06 | 国家电网公司 | The frequency selection circuit that active RLC narrow-band pass filters are combined with Schmidt trigger |
Non-Patent Citations (3)
| Title |
|---|
| A bipolar output voltage pulse transformer boost converter with charge pump assisted shunt regulator for thermoelectric energy harvesting;Ying-Khai Teh等;《Analog Intege Circ Process》;20160212;319-331 * |
| 太赫兹微弱信号检测系统噪声处理方法研究;于东钰等;《应用光学》;20121130;第33卷(第6期);1101-1104 * |
| 太赫兹通信中高速数字信号处理并行化算法;郝鑫等;《太赫兹科学与电子信息学报》;20171231;第15卷(第6期);881-884 * |
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