EP1287320A1 - Method for counting photons in laser-scanning systems - Google Patents

Method for counting photons in laser-scanning systems

Info

Publication number
EP1287320A1
EP1287320A1 EP02722177A EP02722177A EP1287320A1 EP 1287320 A1 EP1287320 A1 EP 1287320A1 EP 02722177 A EP02722177 A EP 02722177A EP 02722177 A EP02722177 A EP 02722177A EP 1287320 A1 EP1287320 A1 EP 1287320A1
Authority
EP
European Patent Office
Prior art keywords
photons
time
laser
threshold
photon
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02722177A
Other languages
German (de)
French (fr)
Inventor
Ralf Wolleschensky
Gunter MÖHLER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Jenoptik AG
Original Assignee
Carl Zeiss Jena GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Carl Zeiss Jena GmbH filed Critical Carl Zeiss Jena GmbH
Publication of EP1287320A1 publication Critical patent/EP1287320A1/en
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J11/00—Measuring the characteristics of individual optical pulses or of optical pulse trains
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors

Definitions

  • the comparator needs a certain (switching time) to get from one state to the other. If the individual photons are so close together that the comparator cannot detect the level changes of the adjacent photons with its switching time, it will only recognize one state and therefore only count one photon.
  • Incoming photons are evaluated two-dimensionally by measuring the amplitude in several threshold values and measuring in a time grid, with a counting frequency at least twice the photon time (empirical duration of the required measurement for a photon), pulses of a higher frequency are counted than that by the photon time prescribed.
  • Comparators, discriminators, triggers, but also in digital form AD converters and associated registers can be used for the threshold value determination.
  • the photon time can be used as the gate time during which an even higher frequency runs into the counter
  • the result can be summarized in a counter or in an adder and read out via a register. After each measurement, the register is cleared again by a clear pulse.
  • the signal to be measured is present at the inputs of the 4 comparators. If the input signal exceeds the switching threshold S1, the tilts Comparator and 'releases the gate circuit (negator and AND operation) via the first negator N1.
  • This formulation F 2lmpulse means that because of the sampling theorem at least two pulses have to be counted per one photon time. The determination of the total number of photons then has a factor of 1/2 in the formula. This results from the definition of at least 2 pulses per photon. If one were to define a 10-fold counting frequency, the factor 1/10 would have to be in the sum formula in order to arrive at the real number of photons. If comparator S2 has reached the threshold, the AND operation of the first comparator is blocked immediately with the output of the comparator and that of the second comparator is opened.
  • the later switching of the second comparator is compensated for by the running time of the signal of the first comparator through the first negator N1, so that the second comparator can still safely block the first gate circuit.
  • the pulses in counter 2 are multiplied by 2 (2xF), those in counter 3 by 3 (3xF) etc. and thus have a higher value than pulses that enter counter 1 via comparator one. This measures the second dimension, since photons in series only generate a higher amplitude, but can take the same time.
  • the switching thresholds S3 and S4 behave in the same way.
  • the counting channels underneath are blocked, whereby the further negators N2, N3 .., as with the first negator, provide for corresponding runtime compensation, so that the second or further gate switching can still be blocked.
  • the highest threshold has priority.
  • the count values Z of the counters i are combined with an adder (summation) and placed as a measured value ZP in a register, for example, and subsequently read and processed by a computer.
  • the combination of the amplitude monitoring and the time measurement of the incoming photons give an exact picture of the actual number of photons that occur within a measurement time.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Measurement Of Unknown Time Intervals (AREA)

Abstract

The invention relates to a method for counting photons in the detection channel of a laser-scanning assembly, preferably a laser-scanning microscope. According to said method, the amplitude of the incoming photons is determined using several thresholds and the threshold determination is coupled to a time-resolved measurement, a respective pulse being counted for individual thresholds and the sum of the counted pulses being determined for the thresholds. For expediency, when a higher threshold is reached, the counted value for the lower threshold is saved for the count.

Description

Verfahren zur Photonenzählung in Laser-Scanning-SystemenProcess for photon counting in laser scanning systems
Es ist bereits bei Laser-Scanning-Mikroskopen bekannt, von einem PMT detektierte Photonen einzeln aufzulösen, indem über einem PMT nachgeordnete Impulsverstärker und Schwellwertschalter wie Komparatoren eine Zählung der Photonen erfolgt - Fig.1.It is already known in laser scanning microscopes to individually resolve photons detected by a PMT by counting the photons via a PMT downstream pulse amplifiers and threshold switches such as comparators - FIG. 1.
In Fig.2 sind typische Beispiele dargestellt wie Fehlmessungen auftreten können.2 shows typical examples of how incorrect measurements can occur.
Übereinanderliegende Photonen haben die gleiche Breite aber eine größere AmplitudeSuperimposed photons have the same width but a larger amplitude
Mit einer Komparator/ Diskriminatorlösung können nur Einzeiphotonen einer festgelegten Amplitude gezählt werden. Wird die eingestellte Schwelle überschritten, dann wird ein Photon erkannt. Wenn zum gleichen Zeitpunkt zwei Photonen auftreffen, dann erhöht sich die Amplitude aber die Schaltschwelle wird auch nur einmal überschritten und damit einmal gezählt. Nebeneinanderliegende ( im Abstand nicht auflösbare Photonen ) sind breiter als ein Photon haben aber gleiche Amplitude.With a comparator / discriminator solution, only single photons of a fixed amplitude can be counted. If the set threshold is exceeded, a photon is recognized. If two photons strike at the same time, the amplitude increases, but the switching threshold is only exceeded once and thus counted once. Adjacent (photons that cannot be resolved at a distance) are wider than a photon but have the same amplitude.
Der Komparator benötigt eine gewisse (Schaltzeit) um von einem Zustand in den anderen zu gelangen. Liegen die einzelnen Photonen so eng aneinander, das der Komparator mit seiner Schaltzeit nicht die Pegeländerungen der nebeneinanderliegenden Photonen erfassen kann wird er nur einen Zustand erkennen und damit auch nur ein Photon zählen.The comparator needs a certain (switching time) to get from one state to the other. If the individual photons are so close together that the comparator cannot detect the level changes of the adjacent photons with its switching time, it will only recognize one state and therefore only count one photon.
Dies ist in Fig.2 schematisch am Beispiel von zwei gleichzeitig auftretenden Photonen, die als eins gezählt werden sowie 5 Photonen dargestellt, wobei in diesem Fall 2 Photonen hintereinanderliegen , die ganz eng mit 3Photonen hintereinander zusammenliegen und damit für den Komparator nur wie ein Photon wirken. Eine denkbare Variante, die Photonenzeit als Torzeit für eine Frequenzmessung zu nutzen, erfaßt genau die ineinanderfließenden Photonen aber nicht die übereinanderliegenden Photonen sodaß auch hier immer eine Ungenauigkeit bleiben wird.This is shown schematically in FIG. 2 using the example of two photons occurring simultaneously, which are counted as one and 5 photons, in this case 2 photons lying one behind the other, which lie very closely together with 3 photons one behind the other and thus only act like a photon for the comparator , A conceivable variant of using the photon time as the gate time for a frequency measurement precisely detects the photons flowing into one another but not the photons lying one above the other, so that an inaccuracy will always remain here as well.
Erfindungsgemäße LösungSolution according to the invention
Ankommende Photonen werden zweidimensional ausgewertet, indem die Amplitude in mehreren Schwellwerten gemessen wird und die Messung in einem Zeitraster erfolgt , mit einer Zählfrequenz mindestend zweifach der Photonzeit ( empirische Dauer der erforderlichen Messung für ein Photon) werden Impulse einer höheren Frequenz gezählt als der durch die Photonenzeit vorgegebene.Incoming photons are evaluated two-dimensionally by measuring the amplitude in several threshold values and measuring in a time grid, with a counting frequency at least twice the photon time (empirical duration of the required measurement for a photon), pulses of a higher frequency are counted than that by the photon time prescribed.
Die Summenbildung aus Amplituden- und Zeitmessung bilden dann die wirkliche Photonenzahl ZPThe sum formation from the amplitude and time measurement then form the actual number of photons ZP
Für die Schwellwertbestimmung können beispielsweise Komparatoren, Diskriminatoren, Trigger, aber auch in digitaler Form AD-Wandler und dazugehörige Register genutzt werden.Comparators, discriminators, triggers, but also in digital form AD converters and associated registers can be used for the threshold value determination.
Für die zeitaufgelöste Bestimmung kann die Photonenzeit als Torzeit genutzt werden währenddessen eine noch höhere Frequenz in den Zähler läuftFor the time-resolved determination, the photon time can be used as the gate time during which an even higher frequency runs into the counter
Das Ergebnis kann sowohl in einem Zähler oder in einem Adder zusammengefaßt werden und über ein Register ausgelesen werden Nach jeder Messung wird das Register wieder durch einen Clear-Impuls gelöscht .The result can be summarized in a counter or in an adder and read out via a register. After each measurement, the register is cleared again by a clear pulse.
Das erfindungsgemäße Prinzip der zweidimensionalen Erfassung von Photonen wird nachstehend anhand Fig. 3 a) und b) beschriebenThe principle of the two-dimensional detection of photons according to the invention is described below with reference to FIGS. 3 a) and b)
Das zu messende Signal liegt gleichzeitig an den Eingängen der 4 Komparatoren an. Überschreitet das Eingangssignal die Schaltschwelle S1 , kippt der Komparator und 'gibt über den ersten Negator N1 die Torschaltung ( Negator und UND-Verknüpfung ) frei.The signal to be measured is present at the inputs of the 4 comparators. If the input signal exceeds the switching threshold S1, the tilts Comparator and 'releases the gate circuit (negator and AND operation) via the first negator N1.
Ist das Eingangssignal nur eine Photonzeit lang, laufen 2 Impulse (die Zählfrequenz ist so gewählt, daß während der Zeitdauer für ein Photon 2 Impulse gezählt werden ) durch die UND-Verknüpfung in den Zähler 1 (x1 ). Wird während der Messzeit ( Pixelzeit eines LSM, Verweildauer zur Erfassung eines Pixels) die Schaltschwelle S2 erreicht und die Impulsbreite des Komparators ist nur eine Photonzeit breit, laufen ebenfalls zwei Impulse über Leitung F, N2 und die UND- Verknüpfung in Zähler 2 ein.If the input signal is only one photon long, 2 pulses run (the counting frequency is selected so that 2 pulses are counted for one photon during the period) through the AND operation in counter 1 (x1). If the switching threshold S2 is reached during the measuring time (pixel time of an LSM, dwell time for recording a pixel) and the pulse width of the comparator is only one photon time wide, two pulses also run via line F, N2 and the AND operation in counter 2.
Diese Formulierung F=2lmpulse heißt, das wegen des Abtasttheorems mindest zwei Impulse pro einer Photonzeit gezählt werden müssen. Die Ermittlung der Gesamtphotonenzahl hat in der Summenformel dann den Faktor 1/2 stehen. Dieser resultiert aus der Festlegung mindestens 2 Impulse pro Photon. Würde man eine 10 fache Zählfrequenz festlegen, so müßte in der Summenformel der Faktor 1/10 stehen um auf die wirkliche Photonenzahl zu kommen. Hat Komparator S2 die Schwelle erreicht, wird sofort mit dem Ausgang des Komparators die UND-Verknüpfung des 1. Komparators gesperrt und die des zweiten Komparators geöffnet. Das spätere Schalten des zweiten Komparators wird durch die Laufzeit des Signales des ersten Komparators durch den ersten Negator N1 kompensiert so daß der zweite Komparator noch sicher die erste Torschaltung sperren kann. Die Impulse im Zähler 2 werden mit 2 (2xF), die imZähler 3 mit 3( 3xF) usw. multipliziert und erhalten somit einen höheren Wert als Impulse die über Komparator eins in den Zähler 1 einlaufen. Damit wird die zweite Dimension gemessen, enn Photonen die hintereinander liegen erzeugen nur eine höhere Amplitude , können aber die gleiche Zeit dauern . Die Schaltschwelle S3 und S4 verhalten sich in gleicher Weise. Jedesmal, wenn eine höhere Schaltschwelle anspricht werden die darunterliegenden Zählkanäle gesperrt, wobei die weiteren Negatoren N2, N3 .. wie beim ersten Negator für eine entsprechende Laufzeitkompensation sorgen, so daß die zweite oder weitere Torschaltungen noch gesperrt werden können. Die jeweils höchste Schwelle hat Priorität. Nach Ablauf der Meßzeit werden die Zählwerte Z der Zähler i mit einem Adder zusammengefaßt (Summenbildung) und als Meßwert ZP z.B. in ein Register gestellt und nachfolgend von einem Computer gelesen und weiterverarbeitet. Bei Impulsen, die nur Komparator eins ansprechen, aber länger als eine Photonezeit dauern sind werden entsprechend mehr Impulse über Leitung F, die UND-Verknüpfung in den Zähler X1 einlaufen. Damit werden verschmolzene bzw. eng aneinanderliegende Photonen erkannt und richtig gezählt und interpretiert.This formulation F = 2lmpulse means that because of the sampling theorem at least two pulses have to be counted per one photon time. The determination of the total number of photons then has a factor of 1/2 in the formula. This results from the definition of at least 2 pulses per photon. If one were to define a 10-fold counting frequency, the factor 1/10 would have to be in the sum formula in order to arrive at the real number of photons. If comparator S2 has reached the threshold, the AND operation of the first comparator is blocked immediately with the output of the comparator and that of the second comparator is opened. The later switching of the second comparator is compensated for by the running time of the signal of the first comparator through the first negator N1, so that the second comparator can still safely block the first gate circuit. The pulses in counter 2 are multiplied by 2 (2xF), those in counter 3 by 3 (3xF) etc. and thus have a higher value than pulses that enter counter 1 via comparator one. This measures the second dimension, since photons in series only generate a higher amplitude, but can take the same time. The switching thresholds S3 and S4 behave in the same way. Whenever a higher switching threshold responds, the counting channels underneath are blocked, whereby the further negators N2, N3 .., as with the first negator, provide for corresponding runtime compensation, so that the second or further gate switching can still be blocked. The highest threshold has priority. After the measurement time has elapsed, the count values Z of the counters i are combined with an adder (summation) and placed as a measured value ZP in a register, for example, and subsequently read and processed by a computer. For impulses that are only comparator one respond, but are longer than a photon time correspondingly more pulses via line F, the AND operation in the counter X1. This means that fused or closely spaced photons are recognized and correctly counted and interpreted.
Die Verbindung der Amplitudenüberwachung und der Zeitmessung der ankommenden Photonen geben ein genaues Abbild der wirklichen Anzahl von Photonen wieder, die innerhalb einer Meßzeit auftreten.The combination of the amplitude monitoring and the time measurement of the incoming photons give an exact picture of the actual number of photons that occur within a measurement time.
Durch Verbesserung der Genauigkeit wird erreichtBy improving the accuracy is achieved
- daß durch mehrstufige Komparatoren unterschiedliche Amplituden des Photonenstromes ausgewertet werden- That different amplitudes of the photon current are evaluated by multi-stage comparators
- daß durch Zeitmessung zusammenhängende Photonen separiert werden können- That contiguous photons can be separated by time measurement
- daß das Ergebnis aus der Amplitudenmessung und der Zeitmessung die genaue Photonenzahl ergibt - That the result of the amplitude measurement and the time measurement gives the exact number of photons

Claims

Patentansprüche 1.Claims 1.
Verfahren zur Photonenzählung im Detektionskanal einer laserscannenden Anordnung, vorzugsweise eines Laser-Scanning -Mikroskopes, wobei eine Amplitudenbestimmung der einlaufenden Photonen mittels mehrerer Schwellwerte erfolgt und die Schwellwertbestimmung mit einer zeitaufgelösten Messung gekoppelt ist, indem für einzelne Schwellwerte jeweils eine Pulszählung erfolgt und die Summe der Zählungen für die Schwellwerte ermittelt wird.Method for counting photons in the detection channel of a laser-scanning arrangement, preferably a laser scanning microscope, whereby the amplitude of the incoming photons is determined by means of several threshold values and the threshold value determination is coupled with a time-resolved measurement, in that a pulse count is carried out for individual threshold values and the sum of the counts for which threshold values are determined.
2. Verfahren nach Anspruch 1 , wobei bei Erreichen eines höheren Schwellwertes der Zählwert des niedrigen Schwellwertes für die Zählung abgespeichert wird. 2. The method according to claim 1, wherein when a higher threshold value is reached, the count value of the low threshold value is stored for the count.
EP02722177A 2001-03-07 2002-03-05 Method for counting photons in laser-scanning systems Withdrawn EP1287320A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10110925A DE10110925A1 (en) 2001-03-07 2001-03-07 Process for photon counting in laser scanning systems
DE10110925 2001-03-07
PCT/EP2002/002375 WO2002071016A1 (en) 2001-03-07 2002-03-05 Method for counting photons in laser-scanning systems

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US (1) US20030183754A1 (en)
EP (1) EP1287320A1 (en)
JP (1) JP2004518979A (en)
DE (1) DE10110925A1 (en)
WO (1) WO2002071016A1 (en)

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Publication number Priority date Publication date Assignee Title
DE10253108B4 (en) * 2002-11-13 2005-11-03 Leica Microsystems Heidelberg Gmbh Method for detecting an object with a scanning microscope and a scanning microscope for detecting an object
DE102006030530A1 (en) * 2006-07-01 2008-01-03 Carl Zeiss Microimaging Gmbh Method and device for detecting light signals
RU2472179C2 (en) * 2007-06-19 2013-01-10 Конинклейке Филипс Электроникс Н.В. Digital pulse processing in multispectral photon counting circuits
DE102009043746A1 (en) 2009-09-30 2011-03-31 Carl Zeiss Microimaging Gmbh Method for generating images with extended dynamic range and optical device for carrying out such a method, in particular a laser scanning microscope
DE102011052334B4 (en) 2011-08-01 2013-04-11 Leica Microsystems Cms Gmbh Device and method for counting photons
DE102017007376B4 (en) 2017-07-20 2023-05-25 Becker & Hickl Gmbh Method and arrangement for recording optical quantum events
JP2021016069A (en) * 2019-07-11 2021-02-12 日本放送協会 Solid-state imaging element and imaging device

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3742491B2 (en) * 1997-07-22 2006-02-01 浜松ホトニクス株式会社 Optical waveform measuring device
US6137566A (en) * 1999-02-24 2000-10-24 Eoo, Inc. Method and apparatus for signal processing in a laser radar receiver
US6355921B1 (en) * 1999-05-17 2002-03-12 Agilent Technologies, Inc. Large dynamic range light detection

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO02071016A1 *

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DE10110925A1 (en) 2002-09-12
WO2002071016A1 (en) 2002-09-12
US20030183754A1 (en) 2003-10-02
JP2004518979A (en) 2004-06-24

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