A key application of quantum technologies overcomes the restrictions of high-performance microscopes, being able to see the molecular vibrations of weak bonds and study biological and metabolic processes, membrane potentials or responses to antibiotics like never before.Our perceptive organs are precious elements, to the point that they led to statements such as Aristotle's, who stated that "there was nothing in the intellect that had not previously been in the senses."But, certainly, the sensors with which we humans are endowed, being very valuable, vitally necessary, are not exactly a paragon of sensitivity.If it is the ear, the range of frequencies to which it is sensitive is between 20 and 20,000 hertz, a very limited range, flanked by ultrasound above and infrasound below.The separation between the ears is directly proportional to the frequency they can capture, as evidenced by elephants.Extremely low frequencies are the natural environment of earthquakes, volcanic eruptions, or the atomic bomb itself.They are frequencies that are poorly absorbed and propagate very well.Ultrasounds are absorbed much more, in addition to the limitation of the size of the objects with which they interact, since the wavelength is much longer.Regarding smell and taste, we would point out that, with few exceptions such as the detection of sulfur compounds, in which the nose is unbeatable, electronic noses or tongues are superior in almost all known records.Touch is already recreated today with pressure detection of less than 15 kilopascals, which is similar to the force used in usual activities such as holding an object or pressing on the screen of our phone.But we do have to highlight an organ of extraordinary value for animal life and, on the other hand, an extremely deficient receptor, capable of capturing electromagnetic oscillations, between about 380 nanometers and about 750 nanometers, which is the smallest interval of wavelengths of the electromagnetic spectrum, leaving out infrared radiation, is what we perceive through touch.We even generate it ourselves, along with microwaves and radio waves, at one end, and ultraviolet radiation, X-rays, gamma rays and cosmic rays at the other.Many species, especially insects, capture ultraviolet light, such as bees that use it effectively to approach flowers and capture nectar, rather than the supposed color attraction.Our sensors are not very sensitive, certainly.As technology advances and we have more and more sophisticated devices, the improvements that evolution could bring in line become more evident.Humans have always tried to improve nature, adapting it to our interests.That is precisely the difference between Science and Technology.The first seeks to know how the processes are produced, the second, once this is known, applies it to transform Nature and make it available to us.In cases, this process goes through improving human qualities.Seeing is essential in humans.How we see is the goal of Science and improving vision is the goal of technology.And once with the technology at our disposal, there are no limits or limiting stages, other than the knowledge available at a given historical moment.Related Topic: Quantum Observation Filmed for the First TimeThe microscope has been a first concretion, when Zacharias Janssen proposed it in 1590, to which many other names would be added, such as Hooke or Malpiagi, always linked to the observation of living cells.They are joined by Abbe or Zeiss.Around the 1930s, the theoretical limit for optical microscopy was reached, despite the fact that interest in observing details of cellular structures was growing.The great contribution that remained derived from questioning the use of light directly, since Quantum had shown that every material particle had a wave associated with it, within the framework of the corpuscle wave duality that De Broglie revealed.Electrons, like protons and neutrons, have associated waves that can be used and specified in the so-called transmission electron microscope, which achieved magnifications of 100,000X, when the optics had stopped at 1000X.In 1931, this microscope was developed in Germany by Knol and Ruska, which was improved shortly after, in 1937, with von Ardene's proposal for a scanning electron microscope, which scanned sample surfaces with a beam of electrons: the response received in the form of particles, it used it to construct a three-dimensional image of the surface being analyzed.It produces high-resolution images from conductive samples, which is achieved by coating them with a metal, and by sweeping the surface with accelerated electrons, it causes particles to detach from the surface that reach the detector, made up of electromagnets that measure the amount and intensity of electrons that reach it after having interacted with the surface of the sample and forming three-dimensional images.Electrons accelerated under a potential difference of 100,000 volts have an associated electromagnetic wave of about 4 picometres, so they allow the observation of the atoms that make up a solid, separated by a couple of tenths of a nanometer, for example.The atomic force microscope proposed by Binning and Rohrer scans the surface with a sharp pyramidal or conical tip, coupled to a flexible microscopic lever: it allows characterizing nanometric (10-9nm) and even atomic (10-10nm) samples for conductive materials , which earned them the 1986 Nobel Prize.The stochastic nature of electromagnetic radiation limits the performance of microscopes based on the use of photons.The sensitivity of radiation-based devices requires a noise level, as it affects resolution and sensitivity.It is not about increasing the intensity of the radiation, since it is not possible in many cases when observing living beings, since the laser radiation, which is appropriate to increase the intensity, while controlling the frequency used, can cause irreparable damage to the living materials to be observed, altering the biological processes under study.The question is to improve the image of the observations of living materials, without increasing the intensity.For this, it has been proposed to use quantum correlation, which allows a signal-to-noise ratio far from the harmful limit that is exceeded in conventional microscopy.The proposal consists, in the first instance, in the use of coherent Raman microscopy, whose resolution is below the wavelength used and, at the same time, uses quantum correlated energies to illuminate.The correlation allows to obtain images of the molecular bonds, significantly improving the signal, with which it is possible to observe biological structures impossible to achieve with other techniques.The quantum enhanced absorption microscopy technique, proposed by Casacio et al.in the journal Nature, it is developed within the framework of coherent Raman scattering microscopy, which involves illumination with quantum correlated energy.Therefore, they are non-linear processes, and as a consequence there is no proportionality between the incident intensity and the response.By the way, the performance of all Raman technologies is very low and, in fact, it was not until lasers were present that Raman spectroscopy advanced.It is illuminated with high intensity visible light to obtain spectra of very low intensity, in areas of the spectrum with lower energy.It is a form of non-linear microscopy that provides a probe to examine the fluorescent vibrational spectrum, therefore, the emission of biomolecules.It allows detecting chemical bonds with great selectivity, the highest currently possible.It opens the doors to study biological, metabolic processes, membrane potentials or responses to antibiotics.The issue to overcome is the damage inflicted by the intensity of illumination associated with Raman processes, which affects the sensitivity and speed of image acquisition and this limits its application.Coherent Raman microscopy is limited by noise associated with illumination intensity.It is not possible to improve the instrumentation in this way.Quantum correlation in coherent Raman microscopy allows noise to be limited and improves the signal-to-noise ratio by up to 35%, allowing properties hidden by signal noise to be revealed.It means overcoming that barrier presented by coherent Raman microscopy, with quantum correlation, which makes it possible to avoid the damage inflicted by light.By exceeding the noise limit of the laser shot, the opportunity is opened to obtain real video image, at the relevant speed, of the molecular vibrations of weak bonds, which were not previously accessible.Sensors using quantum correlation can provide signal-to-noise ratios that bypass the photodamage of conventional techniques.They are a key application of quantum technologies, overcoming the restrictions that existed in the performance of high-performance microscopes, so the proposal can be far-reaching.Every time we delve deeper into the explanation of the intimacy of processes, including those related to life, thanks to technologies that allow us to see where we humans are unable to see, due to lack of acuity.Intimacy is very nonlinear, as we have seen.Processes are never simple.But little by little.(*) Alberto Requena is Professor of Physical Chemistry and Professor Emeritus at the University of Murcia.Quantum-enhanced nonlinear microscopy.Catxere A. Casacio et al.Nature volume 594, pages201–206 (2021).DOI:https://doi.org/10.1038/s41586-021-03528-wSave name and email for the next time you comment.Scientists at the University of California have achieved for the first time the experimental reconstruction of the wave function of electrons, also known as "quantum ghost".A boost to new lasers...A human-like brain helps a robot autonomously exit a maze: The innovation confirms that organic neuromorphic robots can not only learn, but are also capable of moving in...The possibility of hyperluminal space travel leaves the theoretical framework with a proposal that would allow the construction of a prototype of a ship capable of taking us to the Polar Star for tea and bringing us home to...Subscribe to our weekly newsletter.Copyright © 2021. ISSN 2174-6850.Tendencias21 a project of Prensa Ibérica and GLOBAL MEDIA DIGITAL SL 32 years disseminating knowledge (since 1988).