Ari Lehto

PhD, Professor                          In Finnish - Suomeksi

Ari Lehto

PhD in Physics (1978), discovered that the period doubling mechanism, a universal property of nonlinear dynamical systems, governs the buildup of structures from the intrinsic properties of the elementary particles to the large scale systems with cosmological dimensions. 

“The mechanism that indicates a high degree of order in nature is not a part of the prevailing theories but it could give a major contribution to our understanding of the physical reality and the origin of the invariant properties and structures of matter."

Professor emeritus Ari Lehto has generative industrial and academic careers. He is the inventor of novel micro devices and their manufacturing technologies.


Ari Lehto graduated PhD from the Physics Department in the University of Helsinki. Combining theory and practice his professional career led to both industrial and academic positions. Based on his work in Vaisala Corp. in 1980’s Ari Lehto is one of the pioneers of silicon micromechanics based electrically tuneable IR-interferometers (for CO2 and hydrocarbon measurements), pressure sensors and accelerometers widely used in different safety and stability systems in automobiles. His keen interest in the fundamentals of physics did not let the successful industrial work drive him away from science and educational activities; his next positions were in research and educational institutes culminating in a professor’s position at the Helsinki University of Technology. Ari Lehto is inventor of several novel micro devices and their manufacturing technologies.

Ari’s insightful view on materials sciences led him to a search for internal order and invariant properties of matter; a process that after years of patient work led to the discovery of the period doubling mechanism indicating the common roots of material structures — from elementary particles to celestial bodies. Further study of period doubling has confirmed the presence of the mechanism in a wide array of physical systems. “We may live in a far more ordered universe than we may have thought.”


  • University of Helsinki, Department of Physics, PhD (physics) 1978, Assistant and lecturer 1970-1982
  • Vaisala Oy, Researcher and technology development manager 1982-1991
  • Technical Research Centre of Finland, VTT, Research professor 1991-1999
  • Espoo-Vantaa Institute of Technology, Research director at Espoo-Vantaa Institute of Technology 1999-2002
  • Helsinki University of Technology, Professor of materials science and microsystems technology, head of the Laboratory of Materials Science, 2003-2007


  • Docent of applied physics, Department of Physics, University of Helsinki
  • Member of the Finnish Academies of Technology
  • Member of the Finnish Society for Natural Philosophy
  • Member of the Finnish Amateur Radio League


  • Award for the development of silicon pressure microsensor, granted by EIS, The Finnish Electronics Engineering Society, 1987
  • SVR R of the Order of the White Rose of Finland, 1991
  • Vaisala Innovation Award for the development of microsensors, 1993


(most recent at the top)

Ari Lehto, Period-Doubling as a Structure Creating Natural Process, La Nuova Critica, Special Issue 63-64, ISSN 1824-9663 (2016), Scientific Models and a Comprehensive Picture of Reality, pp. 91-115.

Ari Lehto, On the Planck Scale and Properties of Matter, International Journal of Astrophysics and Space Science. Special Issue: Quantum Vacuum, Fundamental Arena of the Universe: Models, Applications and Perspectives. Vol. 2, No. 6-1, 2014, pp. 57-65. doi: 10.11648/j.ijass.s.2014020601.17, Full PDF Paper.

Ari Lehto, On the Planck Scale and Structures of Matter NPA Conference, Storrs, University of Connecticut, May 25-29, 2009, Full text/pdf, Presentation slides.ppt/pdf
Abstract: Invariant properties and structures of matter are modeled by internal period-like degrees of freedom. Invariance then means periods, which remain unaltered over time. Period doubling is a phenomenon common to nonlinear dynamical systems. In this model the doubling process is generalized into multiple dimensions and utilized to bring about sub-harmonic frequencies, which generate decreasing energies and increasing sizes. It is assumed that period doubling takes place at the Planck scale, and therefore the Planck units are used as reference. The sub-harmonics can be converted into several other physical quantities by well known physical relations. A certain class of sub-harmonics is stable and the elementary electric charge (squared), rest energies and magnetic moments of the electron-positron and proton-antiproton pairs are shown to belong to this class. It is suggested that the structure of the Solar system results from period doubling, too.

Ari Lehto, On the Planck Scale and Properties of Matter, Nonlin. Dyn. 55, 279-298 (2009)
Abstract: Invariant and long-lived physical properties and structures of matter are modeled by intrinsic rotations in three and four degrees of freedom. The rotations are quantized starting from the Planck scale by using a nonlinear 1/r potential and period doubling - a common property of nonlinear dynamical systems. The absolute values given by the scale-independent model fit closely with observations in a wide range of scales. A comparison is made between the values calculated from the model and the properties of the basic elementary particles, particle processes, planetary systems, and other physical phenomena. The model also shows that the perceived forces can be divided into two categories: (1) force is always attractive, like in gravitation and (2) force is attractive or repulsive, like in electrostatics.

Ari Lehto, Quantization of Keplerian Systems, (2006)

Ari Lehto, Periodic Time and the Stationary Properties of Matter, Chin. J. Phys., Vol. 28, no. 3, June 1990

Ari Lehto, On (3+3)-Dimensional Discrete Space-Time, University of Helsinki, Report Series in Physics, HU-P-236 (1984).


Handbook of Silicon Based MEMS Materials and Technologies, A volume in Micro and Nano Technologies Veikko Lindroos, Markku Tilli, Ari Lehto and Teruaki Motooka ISBN: 978-0-8155-1594-4


  • H. Ronkainen, A. Hokkanen, M. Kapulainen, A. Lehto, J. Martikainen, I. Stuns, A. Valkonen, S. Varjus and J. Virtanen, Optical sensor for oil film pressure measurement in journal bearings, Proc. 13th Nordic Symposium on Tribology, NORDTRIB 2008 
  • M. Fujikane, S. Nagao, X.W. Liu, D. Chroback, A. Lehto, S. Yamanaga and R. Nowak, Evaluation of carbon doped low-k multilayer structure by nanoindentation, Journal of Alloys and Compounds, 2006 
  • Roman Nowak, Timo Manninen, Kari Heiskanen, Ari Lehto, Fusahito Yoshida, Mike Leszczynski, Jozef Lelatko, Henryk Morawiec, Krzysztof J. Kurzydlowski, Plastic Properties of GaN and Al2O3 Crystal: FEM-Simulation of Nanoindentation Confirmed by High-Resolution Microscopy, invited oral at E-MRS Fall Meeting 2004, Symposium H given by Roman Nowak.
  • Lehto Ari, Piiteknologia - kiekoista systeemeiksi., Materia, 2004. Nr. 4, pp. 26-28.
  • S. Myllymaki, E. Ristolainen, P. Heino, A. Lehto, K. Varjonen, Circular RF MEMS resonator solutions for 100-nm to 10-nm SOI structures, SPIE's International Symposium on Microtechnologies for the New Millennium 2003, 19-21 May, 2003, p.676-681.
  • A. Lehto, P. Heino, E. Ristolainen, S. Myllymäki, K. Varjonen, Evaluation of principal characteristics of circular resonator in thin film applications, Symposium of Design, Test, Integration and Packaging of MEMS/MOEMS, Mandelieu-La Napoule, Cote d’Azur, France, 5-7 May 2003, p. 204-207 
  • S. Myllymaki, E. Ristolainen, P. Heino, A. Lehto, K. Varjonen, Characteristics of Two Types of MEMS Resonator Structures in SOI Applications, 203rd Meeting of The Electrochemical Society, Eleventh International SOI Device Technologies, France, Paris, 27.April-2.May 2003, p. 267-272 S.
  • Myllymaki, E. Ristolainen, P. Heino, A. Lehto, K. Varjonen, Evaluation of resonating channel transistor in SOI wafer, International J. Computational Engineering Science, 4, (3), 711-714, (2003) 
  • S. Myllymaki, E. Ristolainen, P. Heino, A. Lehto, Circular shaped vertical vibration resonator and filtering transistor, Proceedings of Micromechanics Europe workshop, Romania, 6-8 October 2002, b16
  • L. Hietaniemi and A. Lehto, Ympäristömittausten automatisointi- ja kehittämistarpeet Suomessa, Teknologiakatsaus no 117/2001, Ed, Tekes, 2001.
  • H. Valmu, A. Lehto and K. Salmi, Electronics Manufacturing Learning Factory, proc. SEFI 2001 
  • A. Lehto, Getting more out of silicon, High Technology Finland 2000, 46, published by The Finnish Academies of Technology, 2000
  • A. Lehto, Electronics manufacturing learning factory, feasibility study, August 2000 
  • H. Valmu, A. Lehto and K. Salmi, Electronics Manufacturing Learning Factory, Proc. 3’rd European Workshop on Microelectronics Education, ST University, May 18-19, France, 305-7, 2000
  • A. Lehto, SOI Microsensors and MEMS, invited talk, Silicon-on-Insulator Technology and Devices IX, edited by P.L. Hemment, Proceedings of the Electrochemical Society Inc., 11-24, 1999
  • K. Keränen, M. Blomberg, O. Rusanen, P. Karioja, J. Tenhunen, H. Kopola, A. Lehto, Main characteristics of a miniaturized multipurpose infrared spectrometer, Proc. SPIE Vol. 3631, p. 165-172, Optoelectronic Integrated Circuits and Packaging III, Michael R. Feldman; James G. Grote; Mary K. Hibbs-Brenner; Eds. 04/1999
  • A. Lehto, Microsystem Technology: The Technology for the Next Silicon Revolution?, co-author, feasibility study for the PRESTO programme, Tekes report 2/99, 1999
  • O. Rusanen, K. Keränen, M. Blomberg and A. Lehto, Adhesive Flip Chip Bonding in a miniaturized Spectrometer, J. Electronics Manufacturing, 7, 4, 239-243, December 1998  
  • A. Lehto, MEMS research at VTT Electronics, Micro Structure Bulletin, Feb. 1998
  • H. Seppä and A. Lehto, Mekaniikka ja elektroniikka yhteen, Mikromekaanisia antureita, Prosessori, 96-99, Maaliskuu 1998
  • M. Blomberg, O. Rusanen, K. Keränen and A. Lehto, A Silicon Microsystem- Miniaturised Infrared Spectrometer, Proc.Transducers ’97, Chicago, June 16-19, 1257-8, 1997
  • H. Saari and A. Lehto, Micromachined Electrically Tunable Fabry-Perot Interferometer, Proc. 2nd Round Table on Micro/Nano Technologies for Space, 147-150, ESTEC, Netherlands, 15-17 October 1997
  • H. Kopola, P. Karioja, O. Rusanen, A.Lehto and J. Lammasniemi, Hybridization, assembling and testing of miniaturized optoelectronic modules for sensors and microsystems, Miniaturized Systems with Micro-Optics and Micromechanics II, SPIE Vol 3276
  • 1997 K. Keränen, P. Karioja, O. Rusanen, J. Tenhunen, M. Blomberg, A. Lehto, Electrically tuneable NIR-spectrometer, European Symposium on Lasers and Optics in Manufacturing 16 - 20 June 1997, Fairgrounds, Munich, DE. Conference on Micro-Optical Technologies for Measurement, Sensors, and Microsystems II. SPIE Proceedings. SPIE. Bellingham. Vol. 3099, 22, 1997
  • M. Blomberg, A. Torkkeli, A. Lehto, M. Viitasalo, M. Hohtola and Ch. Helenelund, Carbon Dioxide Sensor based on Micromachined Fabry-Perot Interferometer, Proc. Sensor 97, Nurnberg, 13-15 May, 193-8, 1997
  • M. Blomberg, A. Torkkeli, A. Lehto, Ch. Helenelund and M. Viitasalo, Electrically tuneable Fabry-Perot interferometer in gas analysis, Physica Scripta, T69, 119-121, 1997
  • A. Lehto, 3-d period doubling and magnetic moments of particles, Astrophysics and space science, 244, 321-328, 1996
  • E. Ikonen, A. Lehto, P. Wallin and A. Äijälä, Anturitekniikan perusteita, Teknillinen korkeakoulu, Sähkö- ja tietoliikennetekniikan osasto, Mittaustekniikan laboratorio, 1996.
  • H. Kuisma, A. Lehto and J. Lahdenperä, Silicon capacitive pressure sensors, Chemical plants and processing, 22-29, May 1990 A. Lehto, Periodic time and the stationary properties of matter, Chin. J. Phys., 28, 3, 215-235, June 1990.
  • A. Lehto, On (3+3)-dimensional discrete space-time, University of Helsinki, Report series in physics, HU-P 236, 1984
  • J. Jaarinen, A. Lehto and M. Luukkala, Photothermal measurement of the thickness of diffusion hardened layers in steel, Proc. IEEE Ultrason. symp., B.R. McAvoy, Ed, 659-663, 1983
  • M. Luukkala, A. Lehto, J. Jaarinen and M. Jokinen, Photothermal imaging and thermal surface waves as a NDT tool for coatings, Proc. IEEE Ultrason. symp., B.R. McAvoy, Ed, 591-4, 1982
  • J. Saniie, M. Luukkala, A. Lehto and R. Rajala, Thermal wave imaging through radio frequency induction heating, Electronics Letters 18, 15, 651-3, 1982
  • A. Lehto, M. Jokinen, J. Jaarinen and T. Tiusanen and M. Luukkala, Alternating beam method (ABM) in photothermal microscopy (PTM) and photoacoustic microscopy (PAM), Electronics Letters 17, 15, 540, 1981
  • A. Lehto, J. Jaarinen, T. Tiusanen, M. Jokinen and M. Luukkala, Magnitude and phase in thermal wave imaging, Electronics Letters 17, 11, 364, 1981
  • H. Harjunmaa and A. Lehto, Infrared detection using delayed breakdown, Applied Optics 18, 959, 1979
  • A. Lehto, Experimental study of the relaxation of the lower excited s-states of Phosphorus in Silicon at low temperatures, doctor dissertation, 1978
  • A. Lehto and W.G. Proctor, Impurity excited state lifetimes, J. Phys. C: Solid St. Phys 11, 2239-2248, 1978
  • A. Lehto and W.G. Proctor, Delayed avalanche breakdown and donor excited state lifetimes. The Swedish Academy of Engineering Sciences in Finland, report no 31, 1977
  • A. Lehto, Impact excitation of Phosphorus in Silicon at low temperatures, J. Phys. C: Solid St. Phys 10, L 699-703, 1977
  • A. Lehto and W.G. Proctor, Delayed avalanche breakdown in Silicon at low temperatures, J. Phys. C: Solid St. Phys 10, L 481-6, 1977
  • A. Lehto, Lisensiaattityö piin ioni-istutuksesta, Helsingin Yliopisto, Fysiikan laitos, 1974 A. Lehto, Transistorivahvistin, University of Helsinki, Report Series in Physics, 34, 1971
  • A. Lehto, Valon nopeus, University of Helsinki, Report Series in Physics, 19, 1971


  • A. Lehto, H. Ronkainen, J. Koskinen, Menetelmä ja sovitelma kahden pinnan välisen kontaktin monitoroimiseksi, hakemus 2004 (application nro FI 20041622, WO 2006/064086 A1)). 
  • M. Blomberg, A. Lehto, J. Saarilahti, Sensor and method for measuring gas concentrations, EP1160567 (2001)
  • M. Blomberg, A. Torkkeli and A. Lehto, Optically black surface and method for producing the same, US pat 6 177 673 (2001)
  • A. Lehto, H. Kojola, T. Lövgren, H. Lönnberg, Method and device for carrying out a chemical analysis in small amounts of liquid, WO9954730 (1999)
  • A. Lehto, E. Halonen, M. Orpana and A. Utriainen, Overpressure protector, US pat 5 934 307 (1999)
  • M. Blomberg, M. Orpana, H. Kattelus and A. Lehto, Electrically modulatable thermal radiant source with specific filament, US pat 5 827 438 (1998)
  • A. Lehto, S. Lindblad, A. Torkkeli and M. Blomberg, Miniaturized Fabry-Perot spectrometer for optical analysis, US pat 5 818 586 (1998)
  • A. Lehto, M. Orpana, A. Korhonen and S. Tammela, Optical force transducer based on a Fabry-Perot resonator, with a sweeping Fabry-Perot resonator as an element of the transducing part, EP 0 571 107 (1998)
  • A. Lehto, M. Orpana, A. Korhonen and S. Tammela, Optical force transducer based on a Fabry-Perot resonator, EP 0 571 106 (1998)
  • Y. Koskinen, A. Lehto, S. Tammela, M. Blomberg and A. Torkkeli, Single channel gas concentration measurement method and apparatus using a short-resonator Fabry-Perot interferometer, US pat 5 646 729 (1997)
  • M. Blomberg, M. Orpana, A. Lehto and H. Kattelus, Thermal radiant source with filament encapsulated in protective film, US pat 5 644 676 (1997)
  • M. Blomberg, M. Orpana, A. Lehto, Electrically tunable Fabry-Perot interferometer produced by surface micromechanical techniques for use in optical material analysis, US pat 5 561 523 (1996)
  • M. Blomberg, M. Orpana, A. Lehto and A. Korhonen, Electrically modulatable thermal radiant source and method for manufacturing the same, US pat 5 500 569 (1996)
  • A. Lehto, Calibration method for gas concentration measurements, US pat 5 369 278 (1994) A. Lehto, Method and apparatus for measurement of dewpoint of gases, US pat 5 178 462 (1993)
  • A. Lehto, Apparatus and method for determining gas concentrations, US pat 5 160 843 (1992)
  • A. Lehto, H. Kuisma and J. Lahdenperä, Multilayer transducer with bonded contacts and method for implementation of bonding , US pat 5 083 234 (1992)
  • A. Lehto, Method and apparatus for measurement of dewpoint of gases, US pat 5 080 494 (1991) K. Jäppinen, M-R Hakala, J. Jalava and A. Lehto, Field usable calibrator for humidity meters, US pat 4 998 431 (1991)
  • A. Lehto, Integrated heatable sensor, US pat 4 991 424 (1990)
  • A. Lehto and F. Chen, Pressure transducer, US pat 4 928 530 (1990)
  • L. Stormbom, J. Jalava, H. Mesiä, A. Lehto and P.Belt, Method for trimming a planar capacitor, US pat 4 924 064 (1990)
  • I. Kajanto and A. Lehto, Fiberoptic temperature measurement: Method and instrument, SF pat 78353 (1989)
  • A. Lehto, K. Jäppinen and A-M Kärkkäinen, Kapasitiivinen kiihtyvyysanturi ja menetelmä (Capacitive accelerometer and method), SF pat 81915 (1989)
  • A. Lehto, Capacitive pressure detector structure and method for manufacturing the same, US pat 4 597 027 (1986)
  • M. Luukkala and A. Lehto, Procedure and means for examining the surface quality of materials in solid state, US pat 4 551 030 (1985)
  • H. Kuisma, A. Lehto and J. Jalava, Capacitive humidity sensor and method for the manufacture of the same, US pat 4 500 940 (1985)
  • Lehto and H. Harjunmaa, Method for detecting radiation, US pat 4 228 354 (1980)
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