Phase-Sensitive Second Harmonic Microscopy Reveals Bipolar Twinning of Markov-Type Molecular Crystals

Rechsteiner, Peter; Hulliger, Jürg; Flörsheimer, M.

doi:10.1021/cm001018b

Cited by 48 publications

(50 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interferometric second harmonic generation (ISHG) microscopy has been used for imaging noncentrosymmetric materials including organic crystals [14], periodically poled crystals [15] and Beta Barium Borate microcrystals [16], but has not been used at its full potential for tissue imaging. Another technique developed recently called SHG holographic microscopy can also provide phase information about the second harmonic emitters [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Imaging the noncentrosymmetric structural organization of tendon with Interferometric Second Harmonic Generation microscopy

Rivard

Popov

Couture

et al. 2013

Journal of Biophotonics

View full text Add to dashboard Cite

Journal of BIOPHOTONICSWe report the imaging of tendon with Interferometric Second Harmonic Generation microscopy. We observe that the noncentrosymmetric structural organization can be maintained along the fibrillar axis over more than 150 mm, while in the transverse direction it is $1-15 mm. Those results are explained by modeling tendon as a heterogeneous distribution of noncentrosymmetric nanocylinders (collagen fibrils) oriented along the fibrillar axis. The preservation of the noncentrosymmetric structural organization over multiple tens of microns reveals that tendon is made of domains in which the ratio between fibrils with positive and negative polarity is unbalanced.A cross section image representing a laser beam focussed in connective tissue. Collagen fibrils appear as cylinders with a random positive or negative polarity (shown with red or green). The laser intensity profile shows the size of the focal spot.

show abstract

Section: Introductionmentioning

confidence: 99%

Imaging the noncentrosymmetric structural organization of tendon with Interferometric Second Harmonic Generation microscopy

Rivard

Popov

Couture

et al. 2013

Journal of Biophotonics

View full text Add to dashboard Cite

show abstract

“…2). Phase-Sensitive Second Harmonic (Generation) Microscopy (PS-SHM) [32,33] Molecular building blocks showing β ijk optical non-linearity by a polar group in the solid, give rise to sector-wise and polarization dependent frequency doubling. If by interference with a reference 2ω 0 beam, the second harmonic light generated in the crystal (thin layer for transmission, bulk for confocal) is intensified in one sector, whereas in its symmetry related sector destructive interference will take place and vice versa.…”

Section: Wwwcrt-journalorgmentioning

confidence: 99%

Dissymetrization of molecular crystals: a driving force for property formation

Hulliger¹,

Batagiannis

2008

Cryst. Res. Technol.

View full text Add to dashboard Cite

Phenomena of dissymetrization of molecular crystals are reviewed which lead to sector wise polar properties. Orientational disorder of prolate-type dipolar molecules taking place at attachment sites can produce partial polar alignment of dipoles in corresponding growth sectors of molecular crystals nucleating into topologically centric packings. As a result bi-polar crystals are obtained. In case of native polar groups, Monte Carlo simulations predict a basic behaviour for pyroelectric molecular crystals: the dipoles belonging to sectors of either the plus or minus direction of the unique axis show a non-vanishing probability to be gradually reversed. Domain reversal may start upon a single orientational defect developing into complete sector reversal. Basic features of growth induced stochastic polarity formation are confirmed by scanning pyroelectric microscopy, phase sensitive second harmonic generation microscopy and x-ray scattering. Real systems comprise channel-type inclusion compounds, single component molecular crystals, solid solutions and long chain proteins in natural tissues. Neumann's principle gives thought to physical properties of bulk crystals [2], although building blocks undergo attachment to surfaces confined to 2D point groups. For growth induced properties, Neumann's principle may thus be restated as follows [3]: The symmetry elements of a physical property of a growth sector include all symmetry elements of the point group of the growth sector. Properties resulting explicitly from processes at the crystal-nutrient interface are those, which in principle should disappear if thermalization of the bulk structure far off the surface has reached the minimum of free energy. Growth processes leading to the dissymmetrization of crystals are known for a long time [4][5][6] and were mainly discussed for minerals [7]. For a review discussing also molecular crystals featuring optical anomalies [8]. Recently, we have reviewed the impact of surface symmetry on growth-induced properties emerging from corresponding families of faces of the 32 point groups. Explicitly, a symmetry analysis for a vector property, i.e. pyroelectricity was performed [3].Here, we shall understand dissymetrization as a constructive phenomenon for physical property formation. Vector property formation is particularly interesting in the case of molecular crystals, constituted by prolate shaped dipolar molecules. After an extensive experimental [9][10][11][12] and theoretical [3,[13][14][15][16][17][18][19][20][21][22][23] analysis starting in 1995, we are about to conclude that any dipolar molecule crystallizing into a crystal structure described on average by a non-polar point group undergoes (to some extent) sector-wise dissymetrization, leading to sectors showing polar properties. Growth-induced polarity formation leads to non-classical twinning, i.e. bi-polar states of molecular crystals.The basic phenomenon behind growth induced polarity formation is symmetry breaking at the crystalnutrient interface. The probabilities of att...

show abstract

“…[17] These analytical methods allow the mapping of the spatially inhomogeneous distribution of polarity in crystals and thin layers. The lateral resolution of SPEM is presently at about 2.5 mm; in PS-SHM two-dimensional resolution is limited by far-field optics and the wavelength of the fundamental laser light.…”

Section: Markov-chain Model Of Polarity Formationmentioning

confidence: 99%